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Double-Sructure SEM 1<br />
Runn<strong>in</strong>g Head: DOUBLE-STRUCTURE SEM<br />
A Double-Structure Structural Equation Mo<strong>de</strong>l for Three-Mo<strong>de</strong> Data<br />
Jorge González, Paul De Boeck, Francis Tuerl<strong>in</strong>ckx<br />
Department of Psychology, K.U.Leuven, Leuven, Belgium
Double-Sructure SEM 2<br />
Abstract<br />
Structural equation mo<strong>de</strong>ls are commonly used to analyze two-mo<strong>de</strong> data sets, <strong>in</strong> which a set of<br />
objects is measured on a set of variables. The un<strong>de</strong>rly<strong>in</strong>g structure with<strong>in</strong> the object mo<strong>de</strong> is<br />
evaluated us<strong>in</strong>g latent variables which are measured by <strong>in</strong>dicators com<strong>in</strong>g from the variable mo<strong>de</strong>.<br />
Additionally, when the objects are measured un<strong>de</strong>r different conditions, three-mo<strong>de</strong> data arise, and<br />
with this, the simultaneous study of the correlational structure of two mo<strong>de</strong>s may be of <strong>in</strong>terest. In<br />
this paper we present a mo<strong>de</strong>l with a simultaneous latent structure for two of the three mo<strong>de</strong>s of<br />
such a data set. An empirical illustration of the method is presented us<strong>in</strong>g a three mo<strong>de</strong> data set<br />
(person by situaton by response) explor<strong>in</strong>g the structure of anger and irritation across different<br />
<strong>in</strong>terpersonal siutations as well as across persons.<br />
Keywords: Structural equation mo<strong>de</strong>l, three-mo<strong>de</strong> data, <strong>in</strong>dividual differences, situational<br />
differences.
Double-Sructure SEM 3<br />
A Double-Structure Structural Equation Mo<strong>de</strong>l for Three-Mo<strong>de</strong> Data<br />
Structural equation mo<strong>de</strong>ls (SEM) are popular tools <strong>in</strong> the social sciences. They are often<br />
used for <strong>in</strong>vestigat<strong>in</strong>g two-mo<strong>de</strong> data arrays <strong>in</strong> which a set of objects (mo<strong>de</strong> 1) is measured on a set<br />
of variables (mo<strong>de</strong> 2). Examples of such two-mo<strong>de</strong> data sets are abundant. As a specific example,<br />
which will be elaborated <strong>in</strong> the rema<strong>in</strong><strong>de</strong>r of the paper, consi<strong>de</strong>r the case <strong>in</strong> which a group of<br />
persons is asked to answer a set of questions regard<strong>in</strong>g emotional responses to a particular k<strong>in</strong>d of<br />
situation (e.g., various negative-affect responses to a frustrat<strong>in</strong>g situation). In this case, the object<br />
mo<strong>de</strong> consists of a random sample of persons, and the emotional responses comprise the variable<br />
mo<strong>de</strong>. The result<strong>in</strong>g data set is a two-dimensional array of persons by responses. A SEM can then be<br />
used to expla<strong>in</strong> the covariation between the manifest variables (i.e., the emotional responses) by<br />
mak<strong>in</strong>g use of latent variables (and relationships between them). The latent variables mo<strong>de</strong>l<br />
<strong>in</strong>dividual differences.<br />
It is not uncommon, however, for a third mo<strong>de</strong> to be present <strong>in</strong> the data. Follow<strong>in</strong>g the<br />
previous example, consi<strong>de</strong>r P persons who have been asked to answer R questions regard<strong>in</strong>g their<br />
emotions <strong>in</strong><br />
S<br />
different situations. These k<strong>in</strong>ds of data are represented <strong>in</strong> a three-dimensional array<br />
and are referred to as three-mo<strong>de</strong> data (e.g., Kroonenberg, 2005; Cattell, 1946, 1952), <strong>in</strong> which<br />
persons and responses are exten<strong>de</strong>d with a third mo<strong>de</strong> which is, <strong>in</strong> this case, the situation mo<strong>de</strong>. In<br />
other cases it could be time, as <strong>in</strong> a longitud<strong>in</strong>al <strong>de</strong>sign, with moments <strong>in</strong> time <strong>in</strong>stead of situations<br />
as the third mo<strong>de</strong> (Cattell, 1952). Persons, responses, situations, and time, are the four evi<strong>de</strong>nt<br />
mo<strong>de</strong>s that can be used <strong>in</strong> a psychological study. In theory all four mo<strong>de</strong>s can be comb<strong>in</strong>ed <strong>in</strong> one<br />
study, but <strong>in</strong> practice one is either <strong>in</strong>terested <strong>in</strong> the impact of situations, such as contexts and<br />
experimental conditions, or <strong>in</strong> time, as <strong>in</strong> a longitud<strong>in</strong>al study.<br />
For the data that will be analyzed <strong>in</strong> this paper, a set of 679 persons have been measured<br />
with respect to four emotional responses (frustration, ten<strong>de</strong>ncy to act antagonistically, irritation, and
Double-Sructure SEM 4<br />
anger) <strong>in</strong> a set of 11 situations. Thus, the situations are the third mo<strong>de</strong> of the data. Figure 1 shows a<br />
schematic representation of the three-dimensional data array <strong>in</strong> which the observation<br />
y prs<br />
represents the response of person p ( p = 1, …, P) to question r ( r = 1, …, R) <strong>in</strong> situation<br />
s<br />
( s = 1, …,<br />
S).<br />
In the context of the emotional response data set, it can be hypothesized that the propensity<br />
of <strong>in</strong>dividuals to one response will be positively correlated to the propensity to other responses<br />
because of general un<strong>de</strong>rly<strong>in</strong>g traits related to negative and positive affect. On the other hand, it is<br />
possible that an emotional response may be less correlated, or even negatively correlated, to similar<br />
emotional responses when one looks at the responses from a situational perspective because, for<br />
example there is room for only one response at a time, or because there are strong implicit or<br />
explicit situational rules. As a concrete example, the same person may experience both anger and<br />
guilt across situations, but situations that generally provoke anger may be different from those that<br />
provoke guilt (e.g., Vansteelandt, Van Mechelen, & Nezlek, 2005; Zelenski & Larsen, 2000). This<br />
would be reflected <strong>in</strong> a low correlation between anger and guilt across situations, but, it would not<br />
be reflected <strong>in</strong> an analysis of correlated <strong>in</strong>dividual differences, such as <strong>in</strong> the common SEM<br />
approach.<br />
Given that researchers are <strong>in</strong>terested <strong>in</strong> the structures of both the <strong>in</strong>dividual differences and<br />
situational differences, an approach is nee<strong>de</strong>d that allows one to mo<strong>de</strong>l the structures of two si<strong>de</strong>s of<br />
the data array simultaneously. This requires that the psychometric approach and the experimental<br />
approach are comb<strong>in</strong>ed <strong>in</strong> a s<strong>in</strong>gle method, as suggested by Cronbach (1957) <strong>in</strong> his article on the<br />
two discipl<strong>in</strong>es <strong>in</strong> scientific psychology. This is exactly what the double-structure structural equation mo<strong>de</strong>l<br />
(2sSEM) aims to accomplish. If time had been chosen as the third mo<strong>de</strong>, the 2sSEM would allow<br />
for a comb<strong>in</strong>ation of psychometric and <strong>de</strong>velopmental approaches. The comb<strong>in</strong>ed approach allows
Double-Sructure SEM 5<br />
us to evaluate if the between-persons phenonmena can be generalized to the situational or time<br />
facet.<br />
It will be assumed that not only the persons, but also the situations (or moments <strong>in</strong> time) are<br />
sampled from a population (often called a “universe”). In the next step, a jo<strong>in</strong>t mo<strong>de</strong>l will be<br />
specified for the <strong>in</strong>dividual differences and situational differences structure of the data. The notion<br />
of randomly sampled situations is also present <strong>in</strong> other contexts such as the random effects<br />
ANOVA (where the levels of a factor may be consi<strong>de</strong>red a random sample from a larger population)<br />
and <strong>in</strong> generalizability theory (e.g., Cronbach, Rajaratnam & Gleser, 1963; Brennan, 2001), where, <strong>in</strong><br />
the simplest case, the items are consi<strong>de</strong>red a random sample. Treat<strong>in</strong>g the situations as a random<br />
sample is closely l<strong>in</strong>ked with the i<strong>de</strong>a of exchangeability among the situations (see also L<strong>in</strong>dley &<br />
Novick, 1981; Snij<strong>de</strong>rs, 2005). The mo<strong>de</strong>l presented here is an extension of a mo<strong>de</strong>l presented by<br />
De Boeck and Smits (2006) which is, itself, an extension of a basic IRT mo<strong>de</strong>l (i.e., the l<strong>in</strong>ear logistic<br />
test mo<strong>de</strong>l). However, the mo<strong>de</strong>l by De Boeck and Smits (2006) treats only one of the three mo<strong>de</strong>s<br />
as random; the other two are fixed.<br />
Various mo<strong>de</strong>ls for three-mo<strong>de</strong> data can be found <strong>in</strong> the psychometric literature. These<br />
mo<strong>de</strong>ls can be differentiated on the basis of three types of features: (1) the nature of the effects of<br />
mo<strong>de</strong>s: random vs. fixed, (2) the type of <strong>in</strong>teractions among the mo<strong>de</strong>s implicit <strong>in</strong> the mo<strong>de</strong>l, and (3)<br />
the nature of <strong>de</strong>pen<strong>de</strong>nce or <strong>in</strong><strong>de</strong>pen<strong>de</strong>nce among the responses with<strong>in</strong> and across situations and<br />
with<strong>in</strong> and across persons. These three features will be discussed for all mo<strong>de</strong>ls un<strong>de</strong>r consi<strong>de</strong>ration.<br />
For a short overview of these mo<strong>de</strong>ls, and <strong>in</strong> l<strong>in</strong>e with the application that will be <strong>de</strong>scribed later, it<br />
will be assumed that the three mo<strong>de</strong>s are persons, situations, and responses. Table 1 summarizes the<br />
differences among various possible mo<strong>de</strong>ls. In Table 1 we use Fienberg’s (1980; see also Agresti,<br />
2002) notation to express the <strong>in</strong>teractions between variables. The use of the term “<strong>in</strong>teraction” may<br />
seem unusual, but it makes sense when one consi<strong>de</strong>rs that factors and dimensions arise when
Double-Sructure SEM 6<br />
elements of one mo<strong>de</strong> (e.g., persons) differ as a function of elements <strong>in</strong> a different mo<strong>de</strong> (e.g.,<br />
responses).<br />
Two families of three-mo<strong>de</strong> mo<strong>de</strong>ls can be discerned. The first family orig<strong>in</strong>ated with<br />
Tucker (1966), who proposed a three-mo<strong>de</strong> pr<strong>in</strong>cipal-component mo<strong>de</strong>l, now known as the Tucker3<br />
mo<strong>de</strong>l. This type of mo<strong>de</strong>l is the most general one, as far as <strong>in</strong>teractions are concerned, because it<br />
<strong>in</strong>clu<strong>de</strong>s three-way <strong>in</strong>teractions between persons, situations, and responses. Each of the mo<strong>de</strong>s is<br />
analyzed <strong>in</strong> terms of its pr<strong>in</strong>cipal components, and <strong>in</strong> pr<strong>in</strong>ciple, all comb<strong>in</strong>ations (all products) of the<br />
three k<strong>in</strong>ds of components are <strong>in</strong>clu<strong>de</strong>d. The core matrix of these mo<strong>de</strong>ls <strong>de</strong>term<strong>in</strong>es the <strong>de</strong>gree to<br />
which each of the comb<strong>in</strong>ations plays a role. Because three-way <strong>in</strong>teractions are consi<strong>de</strong>red, the<br />
lower-or<strong>de</strong>r effects are implied, unless the data array is first processed to elim<strong>in</strong>ate ma<strong>in</strong> effects (and<br />
possibly also pairwise <strong>in</strong>teractions).<br />
Depend<strong>in</strong>g on the specification of the core matrix, more restricted versions of Tucker3 mo<strong>de</strong>ls can<br />
be obta<strong>in</strong>ed (see Kroonenberg, 1983, for an annotated bibliography). For example, <strong>in</strong> the<br />
CANDECOMP/PARAFAC mo<strong>de</strong>l (Carroll & Chang, 1970; Harshman, 1970), each of the three<br />
mo<strong>de</strong>s has the same number of factors. With<strong>in</strong> each mo<strong>de</strong>, each factor is exclusively l<strong>in</strong>ked to one<br />
factor of each of the other two mo<strong>de</strong>s. As a result the core matrix takes a diagonal shape. In the<br />
orig<strong>in</strong>al Tucker3 family, all parameters are fixed effect parameters (see, the column labeled Tucker3<br />
(a) <strong>in</strong> Table 1). In a further <strong>de</strong>velopment, the parameters referr<strong>in</strong>g to persons are consi<strong>de</strong>red to be<br />
random (e.g., Bloxom, 1968; Bentler & Lee, 1978, 1979; Lee & Fong, 1983; Oort, 1999), as <strong>in</strong>dicated<br />
<strong>in</strong> the column with head<strong>in</strong>g Tucker3 (b) <strong>in</strong> Table 1. When all parameters are fixed, as is commonly<br />
the case for the Tucker3 family, the issue of <strong>de</strong>pen<strong>de</strong>ncy and <strong>in</strong><strong>de</strong>pen<strong>de</strong>nce is irrelevant, as <strong>in</strong>dicated<br />
<strong>in</strong> Table 1. However, if the persons are random, then the <strong>de</strong>pen<strong>de</strong>ncy structure is the same as <strong>in</strong> the<br />
SEM for multitrait-multimethod data. This is expla<strong>in</strong>ed next.
Double-Sructure SEM 7<br />
A second family of mo<strong>de</strong>ls is the set of SEMs for multitrait-multimethod data (MTMM; e.g.,<br />
M. W. Browne, 1984; Eid, 2000; Eid, Lischetzke, Nussbeck, & Trierweiler, 2003; Eid, Lischetzke, &<br />
Nussbeck, 2006). MTMM mo<strong>de</strong>ls are represented <strong>in</strong> the SEM-MTMM column <strong>in</strong> Table 1. Let us<br />
assume that the traits correspond to responses and that the methods correspond to situations. In<br />
such mo<strong>de</strong>ls, two types of factors (latent traits) occur: response (trait) factors, and situation<br />
(method) factors. The effects of trait and method factors on observed responses are additive.<br />
Response factors reflect the <strong>in</strong>teractions between persons and responses and express <strong>in</strong>dividual<br />
differences based on those responses. Situation factors reflect the <strong>in</strong>teractions between persons and<br />
situations, and express how the <strong>in</strong>dividual differences <strong>de</strong>pend on the situations. In other words,<br />
SEM-MTMM is focused on <strong>in</strong>dividual differences, so it is not surpris<strong>in</strong>g that the person mo<strong>de</strong> is<br />
<strong>de</strong>scribed <strong>in</strong> terms of random effects. The mo<strong>de</strong>l utilizes a covariance structure across persons,<br />
which is <strong>de</strong>composed <strong>in</strong>to two k<strong>in</strong>ds of covariation: the first result<strong>in</strong>g from <strong>in</strong>dividual differences<br />
related to responses, and the second from <strong>in</strong>dividual differences related to situations. In SEM-<br />
MTMM, observed variables represent<strong>in</strong>g situation-response pairs responses are assumed to be<br />
<strong>in</strong><strong>de</strong>pen<strong>de</strong>nt across <strong>in</strong>dividuals, but correlated with<strong>in</strong> <strong>in</strong>dividuals.<br />
In contrast to the previous two mo<strong>de</strong>ls (Tucker3 and SEM-MTMM), the 2sSEM mo<strong>de</strong>ls the<br />
<strong>in</strong>teractions of the responses with persons and responses with situations (see Table 1). In the former<br />
case, the latent factors refer to <strong>in</strong>dividual differences, and <strong>in</strong> the latter case they refer to situational<br />
differences. Furthermore, the person mo<strong>de</strong> and the situation mo<strong>de</strong> are both treated as random, so<br />
two different covariance structures are consi<strong>de</strong>red: one over persons and a second over situations.<br />
F<strong>in</strong>ally, the observations from different persons are not required to be <strong>in</strong><strong>de</strong>pen<strong>de</strong>nt, as is the case <strong>in</strong><br />
the SEM-MTMM. Instead, person-situation pairs are assumed to be <strong>in</strong><strong>de</strong>pen<strong>de</strong>nt when they have<br />
neither the person nor the situation <strong>in</strong> common. See Equation 5 for the covariance structure of the<br />
2sSEM. Because the SEM-MTMM is wi<strong>de</strong>ly accepted and commonly used for mo<strong>de</strong>l<strong>in</strong>g person x
Double-Sructure SEM 8<br />
situation x response data, and the 2sSEM we are propos<strong>in</strong>g is relatively novel, we highlight the<br />
differences between the two mo<strong>de</strong>ls; see Table 1 for a summary.<br />
1. Individual differences and situational differences. All latent variables <strong>in</strong> the SEM-MTMM are<br />
<strong>in</strong>dividual-difference variables because the persons are treated as random. In fact, two k<strong>in</strong>ds of<br />
factors are named <strong>in</strong> SEM-MTMM: trait factors and method factors. In the present context,<br />
situations are equivalent to methods. Trait factors refer to <strong>in</strong>teractions between persons and<br />
responses. For example, anger and irritation are two of the responses <strong>in</strong> the example used <strong>in</strong> this<br />
paper. Without any <strong>in</strong>teraction between persons and responses, anger and irritation would have<br />
equal load<strong>in</strong>gs. Generally speak<strong>in</strong>g, if the <strong>in</strong>dividual trait levels do not differentially <strong>de</strong>pend on the<br />
responses, then a s<strong>in</strong>gle factor is required and all load<strong>in</strong>gs will be equal. However, if the <strong>in</strong>dividual<br />
differences do <strong>de</strong>pend on the responses, multiple factors with different load<strong>in</strong>gs are likely. The<br />
presence of more than one factor <strong>in</strong>dicates that there is <strong>in</strong>teraction between persons and responses.<br />
In a similar way, situation (or method) factors refer to <strong>in</strong>teractions between persons and situations<br />
(or methods). Hence, situational factors also refer to <strong>in</strong>dividual differences.<br />
The 2sSEM, also uses two types of latent variables. The first type mo<strong>de</strong>ls <strong>in</strong>dividual<br />
differences, and the second mo<strong>de</strong>ls situational differences. The <strong>in</strong>dividual difference factors come<br />
about as a result of the <strong>in</strong>teraction between persons and responses (i<strong>de</strong>ntical to the SEM-MTMM),<br />
whereas the situational difference factors are due to the <strong>in</strong>teraction between situations and<br />
responses; it captures differences that <strong>de</strong>pend on the situation (but do not vary across <strong>in</strong>dividuals).<br />
Suppose, for example, that a 2sSEM mo<strong>de</strong>l <strong>in</strong>clu<strong>de</strong>s anger and irritation factors. This implies that<br />
some situations tend to generate anger, while other situations are more likely to cause irritation. The<br />
2sSEM and the SEM-MTMM situational factors are, therefore, fundamentally different.
Double-Sructure SEM 9<br />
2. Situations treated as random. In the 2sSEM, <strong>in</strong> contrast with the SEM-MTMM, the situation<br />
mo<strong>de</strong> is also treated as random. This implies that there is a universe of exchangeable situations from<br />
which the researcher has randomly sampled a representative subset with the <strong>in</strong>tend of generaliz<strong>in</strong>g<br />
across all situations. For example, <strong>in</strong> this study we consi<strong>de</strong>r all posible situations that may elicit anger<br />
or irritation and have sampled 11 exangable situations. In contrast, situations or “methods” <strong>in</strong> SEM-<br />
MTMM are fixed and non-enchangeable. There is an <strong>in</strong>herent <strong>in</strong>terest <strong>in</strong> discrim<strong>in</strong>at<strong>in</strong>g among<br />
<strong>in</strong>dividual responses across a few specific and dist<strong>in</strong>ct situations or methods. There could be reasons<br />
to be <strong>in</strong>terested <strong>in</strong> particular situations. For example, <strong>in</strong> a study <strong>in</strong>vestigat<strong>in</strong>g situational differences<br />
<strong>in</strong> anger, one may concentrate on the home environment and the work environment. These<br />
situations are fixed and non-exchangeable and the <strong>in</strong>terest is <strong>in</strong> the covariance among the responses<br />
<strong>in</strong> these two major situations. Another implication of the assumption of random situation <strong>in</strong> 2sSEM<br />
is that the total number of situations is relatively large as compared to the number of fixed methods<br />
<strong>in</strong> SEM-MTMM. It is clear that they are to be treated as fixed and that there is not a large number of<br />
them.<br />
3. In<strong>de</strong>pen<strong>de</strong>nce assumptions. Another important difference between SEM-MTMM and 2sSEM<br />
is the <strong>de</strong>pen<strong>de</strong>nce structure they assume for the observations. In the SEM-MTMM, the observations<br />
from different persons are <strong>in</strong><strong>de</strong>pen<strong>de</strong>nt. However, observations with<strong>in</strong> an <strong>in</strong>dividual (i.e., from<br />
different situation-response pairs) may be <strong>de</strong>pen<strong>de</strong>nt. This is because situation-response pairs, which<br />
constitute the variables or <strong>in</strong>dicators <strong>in</strong> a SEM-MTMM, may correlate due to common (response or<br />
situation) un<strong>de</strong>rly<strong>in</strong>g latent variables. In the 2sSEM, observations with<strong>in</strong> an <strong>in</strong>dividual are expected<br />
to show <strong>de</strong>pen<strong>de</strong>nce (this holds for responses both <strong>in</strong> the same situation and <strong>in</strong> different situations).<br />
However, observations from different persons with<strong>in</strong> the same situation may also be <strong>de</strong>pen<strong>de</strong>nt<br />
upon each other, because the situation may affect all persons <strong>in</strong> the same way. It is only for dist<strong>in</strong>ct<br />
person-situation pairs (with no common elements) that <strong>in</strong><strong>de</strong>pen<strong>de</strong>nce is assumed.
Double-Sructure SEM 10<br />
The rema<strong>in</strong><strong>de</strong>r of the paper is organized as follows: First, we <strong>in</strong>troduce the data set we are<br />
go<strong>in</strong>g to analyze, and formulate the basic research questions. Second, the 2sSEM is <strong>in</strong>troduced us<strong>in</strong>g<br />
the concepts un<strong>de</strong>rly<strong>in</strong>g the regular SEM, and Bayesian methods for mo<strong>de</strong>l estimation, mo<strong>de</strong>l<br />
selection and mo<strong>de</strong>l check<strong>in</strong>g are discussed. To expla<strong>in</strong> the mo<strong>de</strong>l and to compare it with the SEM-<br />
MTMM, the normal l<strong>in</strong>ear version will be used. Next, a three-mo<strong>de</strong> data set (persons by situations<br />
by responses) about four emotions is used to evaluate the mo<strong>de</strong>l, and f<strong>in</strong>ally, conclusions and a<br />
discussion are presented.<br />
Description of the data<br />
A central question <strong>in</strong> emotion research perta<strong>in</strong>s to the differences between irritation and<br />
anger (e.g., Averill, 1982; Frijda, Kuipers, & ter Schure, 1989; Van Coillie & Van Mechelen, 2006).<br />
Although the two emotions can be dist<strong>in</strong>guished quite easily phenomenologically, it is still unclear <strong>in</strong><br />
exactly what ways they differ. The componential theory <strong>in</strong> emotion research forms a fruitful<br />
framework for study<strong>in</strong>g this type of problem (Scherer, Schorr, & Johnstone, 2001).<br />
The basic hypothesis un<strong>de</strong>rly<strong>in</strong>g the theory is that emotions rely on two components: a<br />
feel<strong>in</strong>g component, and an action-ten<strong>de</strong>ncy component, and that the weight of each may differ<br />
<strong>de</strong>pend<strong>in</strong>g on the emotion. Specifically, anger is hypothesized to be more action-oriented than<br />
irritation, whereas irritation is hypothesized to be more feel<strong>in</strong>g-based. In addition, it is hypothesized<br />
that anger is primarily associated with an antagonistic action ten<strong>de</strong>ncy, and to a lesser <strong>de</strong>gree with<br />
frustration, whereas irritation is thought to be primarily associated with the feel<strong>in</strong>g of frustration.<br />
The data <strong>in</strong> this paper came from a sample of 679 Dutch speak<strong>in</strong>g stu<strong>de</strong>nts <strong>in</strong> their last year<br />
of high school (Kuppens, Van Mechelen, Smits, De Boeck, & Ceulemans, 2007). The stu<strong>de</strong>nts were<br />
presented with 11 situations, consi<strong>de</strong>red to be randomly drawn from a population of situations that<br />
might elicit negative emotional responses. They were asked to use a 4-po<strong>in</strong>t scale, rang<strong>in</strong>g from 0<br />
(not at all) to 3 (very strong), to <strong>in</strong>dicate the <strong>de</strong>gree to which they would experience frustration, a
Double-Sructure SEM 11<br />
ten<strong>de</strong>ncy to take antagonistic action, irritation, and anger. To simplify the mo<strong>de</strong>l construction, the<br />
orig<strong>in</strong>al data were dichotomized by recod<strong>in</strong>g the values 0 and 1 as 0, and 2 and 3 as 1. Descriptions<br />
of the 11 situations are shown <strong>in</strong> Table 2.<br />
The histograms <strong>in</strong> Figure 2 show the proportions of positive answers (or endorsements) for<br />
each of the four response types, aggregated over persons (Panel A) and situations (Panel B). Panel A<br />
shows that, on average, approximately 70% of the 11 situations elicited endorsements for anger,<br />
frustration, and antagonistic action. Endorsements for irritation were more common and there is<br />
variability <strong>in</strong> all four responses across the 11 situations. Panel B shows the proportions of<br />
endorsements for each of the four responses and for the 679 persons. The variability across persons<br />
is visible <strong>in</strong> the plots. Many <strong>in</strong>dividuals showed negative affect <strong>in</strong> all of the situations. The skewed<br />
distribution on the manifest level might suggest a problem, but note that this is not necessarily a<br />
problem on the latent level. A normal distribution on the latent level may appear as a skewed<br />
distribution on the manifest level, <strong>de</strong>pend<strong>in</strong>g on the precise values of the situation and response<br />
parameters. These histograms show that, for both situations and persons, there is sufficient<br />
variability to <strong>in</strong>vestigate the covariance structures.<br />
After aggregat<strong>in</strong>g over either the situation or the person mo<strong>de</strong>, the result<strong>in</strong>g two-way data<br />
can be fitted with a standard SEM, however, this approach has serious disadvantages. After<br />
aggregat<strong>in</strong>g over situations, one can only answer questions with respect to <strong>in</strong>dividual differences and<br />
correlations across <strong>in</strong>dividuals. Of course, it is possible to then <strong>in</strong>vestigate the differences and the<br />
correlational structure of the situations by aggregat<strong>in</strong>g over the person mo<strong>de</strong>, but the net result of<br />
these actions is two unrelated mo<strong>de</strong>ls. For example, when aggregat<strong>in</strong>g over situations, it is possible<br />
to <strong>in</strong>vestigate whether persons who tend to be angry also tend to be irritated. Or, when aggregat<strong>in</strong>g<br />
over persons, one might ask whether situations which tend to elicit anger also tend to elicit irritation.
Double-Sructure SEM 12<br />
The relationships between emotional responses <strong>in</strong> these two mo<strong>de</strong>ls may be similar, but this is not<br />
required<br />
The basic research questions addressed with these data are (see Figure 3 for a graphical<br />
representation):<br />
1. What is the structure of the <strong>in</strong>dividual differences? If each emotional response<br />
(frustration, antagonistic action ten<strong>de</strong>ncy, irritation, anger) is consi<strong>de</strong>red a separate<br />
latent variable over which <strong>in</strong>dividuals can differ, how are these latent variables related<br />
to one another? Is frustration the primary component of irritation (i.e., versus<br />
antagonistic action ten<strong>de</strong>ncy), and the ten<strong>de</strong>ncy to act antagonistically the primary<br />
component of anger (i.e., versus frustration)? In terms of Figure 3 the hypothesis<br />
implied by the first research question is that a> c, and d > b.<br />
2. What is the structure on the situation si<strong>de</strong>? Is it also the case for situations that<br />
frustration is the primary component of irritation, and that antagonistic action<br />
ten<strong>de</strong>ncy is the primary component of anger? The hypothesis is aga<strong>in</strong> that<br />
a<br />
> c<br />
, and<br />
d<br />
> b<br />
<strong>in</strong> Figure 3, but now the figure refers to situations rather than <strong>in</strong>dividuals.<br />
3. If the structures of the person si<strong>de</strong> and the situation si<strong>de</strong> are similar, as hypothesized<br />
<strong>in</strong> 1 and 2, are the population values for effects that l<strong>in</strong>k the four latent variables the<br />
same for persons and situations? In Figure 3, this hypothesis states that the<br />
standardized values for abcd , , , , are i<strong>de</strong>ntical for the structure of <strong>in</strong>dividual<br />
differences and the structure of the situational differences. The hypothesis is phrased<br />
<strong>in</strong> terms of standardized values, <strong>in</strong> or<strong>de</strong>r for the estimates to be <strong>in</strong><strong>de</strong>pen<strong>de</strong>nt of the<br />
variances.
Double-Sructure SEM 13<br />
It is neither a statistical nor psychological necessity that the structures for the two mo<strong>de</strong>s be<br />
i<strong>de</strong>ntical or even similar. For example, the structure may be one-dimensional for the persons, with<br />
all four emotional responses result<strong>in</strong>g from a s<strong>in</strong>gle general factor; whereas situations may require<br />
multiple dimensions to expla<strong>in</strong> the same four emotional responses.<br />
Double-structure Structural Equation Mo<strong>de</strong>l (2sSEM)<br />
In this section, the 2sSEM that takes <strong>in</strong>to account both <strong>in</strong>dividual and situational differences<br />
will be <strong>de</strong>scribed. Follow<strong>in</strong>g Bollen (1989), a SEM encompasses two parts. The first part is the<br />
measurement mo<strong>de</strong>l which conta<strong>in</strong>s the equations represent<strong>in</strong>g the l<strong>in</strong>k between the observed and latent<br />
variables. The second part is the structural mo<strong>de</strong>l which conta<strong>in</strong>s the equations that represent the<br />
hypothesized relations between the latent variables. We will explicitly <strong>de</strong>f<strong>in</strong>e the measurement and<br />
structural mo<strong>de</strong>l used for the study of both <strong>in</strong>dividual and situational differences simultaneously.<br />
For ease of presentation, the 2sSEM will be <strong>in</strong>troduced us<strong>in</strong>g cont<strong>in</strong>uous observed<br />
variables. However, because the data of our central application are b<strong>in</strong>ary, we will later <strong>de</strong>monstrate<br />
how the 2sSEM can be exten<strong>de</strong>d <strong>in</strong> a straightforward manner to handle dichotomous data.<br />
The 2sSEM<br />
In a general formulation of the mo<strong>de</strong>l, assume that there are<br />
Q<br />
latent person variables and<br />
T<br />
latent situation variables. The follow<strong>in</strong>g notation will be used: the observed random variable<br />
y<br />
prs<br />
represents the “magnitu<strong>de</strong>” of person p ’s response<br />
r<br />
<strong>in</strong> situation s . In the emotion data set, the<br />
<strong>in</strong><strong>de</strong>x<br />
r<br />
may take one of four values: 1, 2, 3, or 4; which correspond to frustration, antagonistic<br />
PER<br />
action ten<strong>de</strong>ncy, irritation, and anger, respectively. The symbol η<br />
pq<br />
refers to the score for person<br />
p on the q -th latent trait ( q = 1, …, Q) . The superscript PER is somewhat superfluous because the<br />
subscript<br />
p already <strong>in</strong>dicates that the latent trait refers to the person si<strong>de</strong> and not the situation si<strong>de</strong>.<br />
However, for the factor load<strong>in</strong>gs (λs, as <strong>in</strong> Equation 1) this difference will not be as clear so we will
Double-Sructure SEM 14<br />
reta<strong>in</strong> the superscript notation. Likewise, η refers to the score for situation s on the t -th latent<br />
SIT<br />
st<br />
trait<br />
( t = 1, …T , ). The effect of responses will be represented by τ<br />
r<br />
. From the <strong>de</strong>scription of the<br />
effects it will be clear whether an effect is fixed or random.<br />
Measurement mo<strong>de</strong>l. The measurement mo<strong>de</strong>l we use is<br />
Q<br />
T<br />
PER PER SIT SIT <br />
PER PER<br />
<br />
SIT SIT<br />
prs ∑ rq<br />
ηpq ∑λrt ηst τr ε<br />
prs λr<br />
ηp<br />
λr<br />
ηs<br />
τr ε<br />
pr<br />
q= 1 t=<br />
1<br />
y = λ + + + = + + +<br />
s,<br />
where λ is the load<strong>in</strong>g of response r on the q -th ( q = 1, …, Q) latent person variable, and<br />
PER<br />
rq<br />
SIT<br />
λ<br />
rt<br />
(1)<br />
is the load<strong>in</strong>g of response r on the t -th ( t = 1, …T , ) latent situation variable. τ<br />
r<br />
is the fixed general<br />
PER SIT<br />
effect for response r , and ε<br />
prs<br />
is a random error term with mean zero. Both η<br />
pq<br />
and η<br />
st<br />
are<br />
random variables, which will be <strong>de</strong>scribed when the structural mo<strong>de</strong>l is presented.<br />
The measurement mo<strong>de</strong>l <strong>in</strong> Equation 1 can also be written <strong>in</strong> matrix form. First, all<br />
responses perta<strong>in</strong><strong>in</strong>g to the same person-situation comb<strong>in</strong>ation are collected <strong>in</strong> the R × 1 vector,<br />
<br />
PER<br />
SIT<br />
y . The row vectors of load<strong>in</strong>gs ( λ r and λ PER<br />
r ) are stacked <strong>in</strong> the load<strong>in</strong>g matrices Λ and<br />
ps<br />
SIT<br />
Λ<br />
, respectively, and the<br />
τ<br />
r<br />
parameters gathered <strong>in</strong> one R × 1 vector<br />
τ . The mo<strong>de</strong>l then becomes:<br />
or<br />
PER PER SIT SIT<br />
=<br />
ps Λ +<br />
p Λ + τ +<br />
s<br />
ps,<br />
y η η ε<br />
(2)<br />
y<br />
λ λ η λ λ<br />
⎛ ⎞ ⎛ PER PER ⎞⎛ PER ⎞ ⎛ SIT SIT ⎞⎛ SIT ⎞ ⎛ ⎞ ⎛ ⎞<br />
⎜ p1s ⎟ ⎜ 11 1Q ⎟⎜ p1 ⎟ ⎜ 11<br />
<br />
1T<br />
⎟⎜ ⎜ ⎟⎜ ⎟<br />
s1<br />
⎟ ⎜ 1 ⎟ ⎜ p1s<br />
⎟<br />
⎜ ⎟<br />
⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ ⎟<br />
⎜ ⎟ ⎜ ⎟⎜ ⎟<br />
⎜<br />
<br />
⎜ ⎟⎜ ⎟<br />
⎟ ⎜ ⎟⎜ <br />
⎜ ⎟ ⎜ ⎟<br />
⎟ ⎜ ⎟⎜ ⎟ ⎜<br />
⎜<br />
<br />
⎟ ⎟<br />
⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟⎜ ⎟<br />
⎜<br />
PER PER PER<br />
⎜ ⎟ ⎜ ⎟<br />
SIT SIT<br />
y ⎟ ⎜<br />
prs = λr1 λ<br />
⎟⎜<br />
rQ<br />
η<br />
⎟<br />
⎜ ⎟ ⎜<br />
<br />
⎟⎜ pq ⎟+<br />
⎜ SIT<br />
λr1<br />
λ<br />
⎟⎜ rT<br />
η<br />
⎟+ ⎜τ<br />
⎟<br />
st r<br />
+ ⎜ε<br />
⎟<br />
⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ prs ⎟<br />
⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ ⎟<br />
⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ ⎟<br />
⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ ⎟<br />
⎜ ⎟ ⎜ PER PER ⎟⎜ PER ⎟ ⎜ SIT<br />
SIT ⎟⎜ SIT ⎟ ⎜ ⎟<br />
⎜y<br />
pRs ⎟ ⎜λR 1<br />
λ ⎟⎜<br />
RQ<br />
η ⎟<br />
pQ<br />
⎜λ<br />
τ ε<br />
⎝ ⎠ ⎝ ⎠⎝ ⎠ R1<br />
λ ⎟⎜ RT<br />
η ⎟ ⎜ ⎟<br />
sT R<br />
⎜ pRs ⎟<br />
⎝ ⎠⎝<br />
⎠ ⎝ ⎠ ⎝ ⎠<br />
η<br />
τ<br />
ε<br />
. (3)<br />
In a mo<strong>de</strong>l for cont<strong>in</strong>uous and normally distributed data, one may also assume that<br />
ε ps ∼ N ( 0,<br />
Φ)
Double-Sructure SEM 15<br />
where Φ is an R × R variance-covariance matrix of the error terms. Usually Φ is taken to be<br />
diagonal. Note that we will <strong>de</strong>f<strong>in</strong>e a different distribution for the measurement error terms <strong>in</strong> the<br />
case of b<strong>in</strong>ary data. In the most general case, there are as many latent variables as there are responses<br />
(Q = R and T = R). However, it is perfectly possible to formulate a mo<strong>de</strong>l <strong>in</strong> which Q < R and<br />
T<br />
< R, and also Q ≠ T . Given that, <strong>in</strong> the example, Q = R and T = R, note that y to y are<br />
pr1<br />
prS<br />
PER<br />
multiple <strong>in</strong>dicators for η<br />
pr<br />
, and similarly y<br />
1rs<br />
to<br />
Prs<br />
y are multiple <strong>in</strong>dicators for<br />
SIT<br />
η<br />
sr<br />
.<br />
(Double-structure) structural mo<strong>de</strong>l. The two-fold structural mo<strong>de</strong>l can now be <strong>de</strong>f<strong>in</strong>ed as<br />
follows:<br />
η = B η +<br />
(4)<br />
p<br />
PER PER PER PER<br />
p<br />
p<br />
ζ<br />
η = η + ζ ,<br />
SIT SIT SIT SIT<br />
s B s s<br />
PER<br />
SIT<br />
where B and B are Q × Q and T× T parameter matrices for regressions among the Q latent<br />
person variables and among the T latent situation variables, respectively; and<br />
PER<br />
SIT<br />
residual vectors. It is assumed that both ( I−<br />
B ) and ( − )<br />
PER<br />
ζ and<br />
p<br />
SIT<br />
ζ<br />
s<br />
are<br />
I B are nons<strong>in</strong>gular. A value of zero<br />
<strong>in</strong> a<br />
B<br />
matrix means that there is no effect of one latent variable on another. In particular, the<br />
PER<br />
SIT<br />
diagonals of both B and B always conta<strong>in</strong> only zeroes, mean<strong>in</strong>g that a variable is not<br />
expla<strong>in</strong>ed by itself.<br />
Note that, <strong>in</strong> Equation 4, a structure is imposed on both the person latent variables and the<br />
situation latent variables. Both<br />
PER<br />
η p<br />
and<br />
SIT<br />
η<br />
s<br />
conta<strong>in</strong> subvectors of latent explanatory (<strong>in</strong><strong>de</strong>pen<strong>de</strong>nt<br />
or exogenous) and latent response (<strong>de</strong>pen<strong>de</strong>nt or endogenous) variables. The residual vectors<br />
PER<br />
ζ<br />
p<br />
and<br />
SIT<br />
ζ<br />
s<br />
follow normal distributions<br />
PER<br />
N ( 0,<br />
Ψ ), and<br />
SIT<br />
N ( , )<br />
PER<br />
0 Ψ , respectively, <strong>in</strong> which Ψ and<br />
SIT<br />
Ψ<br />
conta<strong>in</strong> covariances with<strong>in</strong> and between the sets of explanatory and expla<strong>in</strong>ed variables. In the
Double-Sructure SEM 16<br />
mo<strong>de</strong>ls that will be consi<strong>de</strong>red here, these covariances are assumed to be zero when an expla<strong>in</strong>ed<br />
variable is <strong>in</strong>volved, but not when both variables are explanatory.<br />
The standard graphical way of represent<strong>in</strong>g the SEM is a path diagram (e.g., Bollen, 1989).<br />
This graphical representation of a system of simultaneous equations can be transferred to the<br />
2sSEM as well. Directional <strong>in</strong>fluence between the variables is represented by s<strong>in</strong>gle-hea<strong>de</strong>d arrows,<br />
and curved two-hea<strong>de</strong>d arrows represent correlations. In the application that follows, we will make<br />
use of the graphical representation to <strong>in</strong>troduce several mo<strong>de</strong>ls (see Figure 4). The observed<br />
variables and error terms are omitted from the path diagrams for clarity.<br />
Hav<strong>in</strong>g <strong>de</strong>f<strong>in</strong>ed this mo<strong>de</strong>l, it is possible to <strong>de</strong>rive the mo<strong>de</strong>l-implied covariance matrices<br />
between the response vectors<br />
y and<br />
ps<br />
ps ′ ′<br />
y :<br />
−1<br />
PER PER −1 PER PER PER<br />
Cov( y , y ) = Λ ( I−B ) Ψ ( I−B<br />
) Λ <br />
+ (5)<br />
ps<br />
p′′<br />
s<br />
−1<br />
SIT SIT −1 SIT SIT SIT<br />
Λ ( I−B ) Ψ ( I− B ) Λ <br />
+ Φ if p = p′ and s=<br />
s′<br />
−1<br />
PER PER −1 PER PER PER<br />
= Λ ( I−B ) Ψ ( I− B ) Λ <br />
if p = p′ and s≠<br />
s′<br />
−1<br />
SIT SIT −1 SIT SIT SIT<br />
= Λ ( I−B ) Ψ ( I−B<br />
) Λ <br />
if p ≠ p′ and s=<br />
s′<br />
= 0 if p ≠ p′ and s ≠ s′<br />
.<br />
As can be seen, <strong>in</strong> the l<strong>in</strong>ear 2sSEM, the mo<strong>de</strong>l-implied covariance is non-zero for responses<br />
<strong>in</strong> two person-situation pairs that have at least one common element.<br />
The mo<strong>de</strong>l-implied covariance for a SEM-MTMM is a little different. The covariance is 0<br />
when p ≠ p′ and it is Δ+ Θ+<br />
Ξ when p = p′ . The symbols Δ , Θ , and Ξ refer to the trait<br />
covariance (covariance between <strong>in</strong>dividual differences <strong>in</strong> the traits), the situation covariance<br />
(covariance between <strong>in</strong>dividual differences associated with the situations), and the residual<br />
covariance matrices, respectively. All three refer to <strong>in</strong>dividual differences.<br />
F<strong>in</strong>ally, note that the implied covariance structures only hold un<strong>de</strong>r the normal l<strong>in</strong>ear mo<strong>de</strong>l.<br />
In the rema<strong>in</strong><strong>de</strong>r of the paper we will work with discrete (b<strong>in</strong>ary) data. For such data it is less trivial<br />
(but also less <strong>in</strong><strong>format</strong>ive) to <strong>de</strong>rive the implied covariance structure. However, it is still the case
Double-Sructure SEM 17<br />
that, un<strong>de</strong>r the 2sSEM, responses of different persons <strong>in</strong> the same situation and responses of the<br />
same person <strong>in</strong> different situations are both permitted to be <strong>de</strong>pen<strong>de</strong>nt (as well as responses by the<br />
same <strong>in</strong>dividual <strong>in</strong> the same situation).<br />
The mo<strong>de</strong>l for dichotomous data<br />
A latent threshold formulation will be used to make the mo<strong>de</strong>l suitable for analyz<strong>in</strong>g b<strong>in</strong>ary<br />
data (<strong>de</strong>tails are given <strong>in</strong> Appendix A). Un<strong>de</strong>r this formulation, the measurement mo<strong>de</strong>l <strong>in</strong> Equation<br />
PER SIT<br />
1 becomes a mo<strong>de</strong>l for the conditional probability π = Pr( y = 1| η , η ) , and is expressed as:<br />
prs prs p s<br />
π<br />
prs<br />
= F + η + τ ). (6)<br />
<br />
PER PER<br />
<br />
SIT<br />
( λ r η p λ r<br />
SIT<br />
s<br />
r<br />
We chose F to be F( x) = exp( x) /(1 + exp( x))<br />
, lead<strong>in</strong>g to a logistic mo<strong>de</strong>l of the form<br />
⎛ π ⎞<br />
prs<br />
<br />
PER PER<br />
log = logit( π<br />
prs<br />
) = r p +<br />
⎜<br />
1−π<br />
⎟<br />
λ η λ<br />
⎝ prs ⎠<br />
<br />
SIT<br />
r<br />
η<br />
SIT<br />
s<br />
+ τ . (7)<br />
r<br />
The scale of the person and situation latent variables is the same <strong>in</strong> terms of the effect on the<br />
logit scale, but the scale is not standardized with respect to variance. Other selections of<br />
F are<br />
possible, as well (e.g., if F<br />
equals the standard normal cumulative distribution function, the result is<br />
a probit mo<strong>de</strong>l). The approach taken here to accommodate b<strong>in</strong>ary variables (and elaborated <strong>in</strong><br />
Appendix A) can be exten<strong>de</strong>d easily to, for <strong>in</strong>stance, ord<strong>in</strong>al data, by us<strong>in</strong>g the Generalized L<strong>in</strong>ear<br />
Mo<strong>de</strong>l framework (GLM; McCullagh & Nel<strong>de</strong>r, 1989). For or<strong>de</strong>red-category data, one must make a<br />
choice between adjacent and cumulative logits. That is, either a given category is compared the one<br />
immediately below it, (adjacent logit), or the category of <strong>in</strong>terest, together with all higher categories,<br />
is compared with all lower categories (cumulative logit). A simple way of do<strong>in</strong>g this is to assume that<br />
the distance between the category thresholds is the same for all responses, so that the Rat<strong>in</strong>g Scale<br />
Mo<strong>de</strong>l (RSM; Andrich, 1978) can be used for either adjacent or cumulative logits. Skrondal and
Double-Sructure SEM 18<br />
Rabe-Hesketh (2004) discuss how GLMs may be <strong>in</strong>corporated <strong>in</strong>to SEMs. Such an approach greatly<br />
expands the area of application.<br />
Statistical Inference<br />
The 2sSEM <strong>in</strong>clu<strong>de</strong>s random effects for two of the three mo<strong>de</strong>s <strong>in</strong> the data and therefore, it<br />
is a crossed-random effects mo<strong>de</strong>l (e.g., Snij<strong>de</strong>rs & Bosker, 1999; Janssen, Schepers, & Peres, 2004;<br />
Janssen, Tuerl<strong>in</strong>ckx, Meul<strong>de</strong>rs, & De Boeck, 2000). When data are not normally distributed (such<br />
that the <strong>in</strong>tegral over the latent distribution has no analytic solution), the estimation of mo<strong>de</strong>l<br />
parameters is not trivial (Tuerl<strong>in</strong>ckx, Rijmen, Verbeke, & De Boeck, 2006). In this case, the<br />
likelihood conta<strong>in</strong>s an <strong>in</strong>tegral of a very high dimension because, unlike a traditional random effects<br />
mo<strong>de</strong>l, it cannot be factorized <strong>in</strong>to separate contributions of the persons (because the responses of<br />
different persons are not <strong>in</strong><strong>de</strong>pen<strong>de</strong>nt). The dimension of the <strong>in</strong>tegral over the latent trait<br />
distributions is, at m<strong>in</strong>imum, as high as the sum of the number of elements of the mo<strong>de</strong>s with<br />
random effects (<strong>in</strong> the central example <strong>in</strong> this paper, that would mean at least 690 dimensions), but<br />
<strong>in</strong> most cases, the dimensionality will be larger.<br />
For such cases, the well known Gauss-Hermite quadrature method becomes unfeasible,<br />
because of the high dimensionality of the <strong>in</strong>tegrals <strong>in</strong> the likelihood function. Also Laplace<br />
approximations tend to break down because the dimensionality grows as a function of the sample<br />
size (e.g., Shun & McCullagh, 1995; Shun, 1997). Possible alternative solutions are Monte-Carlo and<br />
Quasi-Monte Carlo methods for numerical <strong>in</strong>tegration (e.g., González, Tuerl<strong>in</strong>ckx, De Boeck, &<br />
Cools, 2006); or Bayesian methodology, which was used <strong>in</strong> this paper. In the follow<strong>in</strong>g section, we<br />
outl<strong>in</strong>e the Bayesian method that was used for to estimate the 2sSEM. Details of the estimation and<br />
software implementation are given <strong>in</strong> Appendix B and the onl<strong>in</strong>e supplementary material,<br />
respectively. Rea<strong>de</strong>rs <strong>in</strong>terested <strong>in</strong> more <strong>in</strong><strong>format</strong>ion about the Bayesian approach for SEMs are<br />
referred to Lee (2007).
Double-Sructure SEM 19<br />
Bayesian estimation<br />
Bayesian <strong>in</strong>ference is based on the posterior distribution of all parameters of <strong>in</strong>terest, given<br />
the observed data. Let ϑ be the vector of parameters, as well as latent variables and y the observed<br />
data. For the 2sSEM, ϑ conta<strong>in</strong>s all of the parameters <strong>in</strong> the matrices<br />
PER SIT PER SIT PER SIT<br />
B , B , Λ , Λ , Ψ , Ψ ,τ,<br />
and the latent residuals<br />
ζ , ζ . If y| ϑ ∼ f ( y| ϑ ), then<br />
PER<br />
p<br />
SIT<br />
s<br />
Bayes’ theorem leads to the follow<strong>in</strong>g relation<br />
f( ϑ | y) ∝ f( y| ϑ) f( ϑ ),<br />
(8)<br />
which shows that the posterior <strong>de</strong>nsity is proportional to the likelihood function times the prior. A<br />
sample is obta<strong>in</strong>ed from the posterior distribution and the posterior mean and posterior standard<br />
<strong>de</strong>viation and confi<strong>de</strong>nce <strong>in</strong>tervals are used to summarize the distribution of each parameter of<br />
<strong>in</strong>terest.<br />
In or<strong>de</strong>r to obta<strong>in</strong> a sample from the posterior distribution, different iterative methods<br />
belong<strong>in</strong>g to the class of Markov Cha<strong>in</strong> Monte Carlo (MCMC) techniques (e.g., Gelman, Carl<strong>in</strong>,<br />
Stern, & Rub<strong>in</strong>, 2003) have been <strong>de</strong>veloped. After the prior distributions are specified for all the<br />
parameters <strong>in</strong> the mo<strong>de</strong>l, these algorithms generate a Markov Cha<strong>in</strong>. Follow<strong>in</strong>g an <strong>in</strong>itial burn-<strong>in</strong><br />
period (which often consists of several thousand iterations), the draws can be used as a sample from<br />
the posterior distribution <strong>in</strong> Equation 8 on the condition that convergence is reached (which can be<br />
approximately checked us<strong>in</strong>g the R diagnostic; Gelman & Rub<strong>in</strong>, 1992).<br />
W<strong>in</strong>BUGS (Spiegelhalter, Thomas, Best, & Lunn, 2003) is a software program for Bayesian<br />
analysis of statistical mo<strong>de</strong>ls us<strong>in</strong>g MCMC techniques. After the user provi<strong>de</strong>s a likelihood and prior<br />
distribution, the program automatically draws a sample of all parameters from the posterior<br />
distribution. Once convergence has been reached, parameter estimates can be obta<strong>in</strong>ed and<br />
<strong>in</strong>ferences ma<strong>de</strong>.
Double-Sructure SEM 20<br />
All mo<strong>de</strong>ls <strong>in</strong> this paper were fitted with W<strong>in</strong>BUGS , which was called from R (R<br />
Development Core Team, 2006) by us<strong>in</strong>g the R2W<strong>in</strong>BUGS package (Sturtz, Ligges, & Gelman,<br />
2005). Convergence was assessed us<strong>in</strong>g the CODA package (Plummer, Best, Cowles, & V<strong>in</strong>es,<br />
2006), which implements standard convergence criteria (e.g., Cowles & Carl<strong>in</strong>, 1996). The ma<strong>in</strong><br />
R/W<strong>in</strong>BUGS co<strong>de</strong> that was used is available as supplementary material onl<strong>in</strong>e.<br />
Bayesian mo<strong>de</strong>l selection and mo<strong>de</strong>l check<strong>in</strong>g<br />
When different mo<strong>de</strong>ls for data are fitted, the researcher is confronted with a mo<strong>de</strong>l<br />
selection issue: which mo<strong>de</strong>l fits the data best among the set of mo<strong>de</strong>ls un<strong>de</strong>r consi<strong>de</strong>ration. S<strong>in</strong>ce<br />
we are work<strong>in</strong>g <strong>in</strong> a Bayesian framework, we may calculate Bayes factors (Kass & Raftery, 1995) and<br />
select the mo<strong>de</strong>l with largest posterior probability given the data. However, it is quite<br />
computationally <strong>de</strong>mand<strong>in</strong>g to compute Bayes factors, and therefore we consi<strong>de</strong>red other solutions.<br />
The AIC (Akaike, 1974) and BIC (Schwarz, 1978) provi<strong>de</strong> alternative measures. However, these<br />
criteria are <strong>de</strong>rived <strong>in</strong> frequentist framework and, therefore, less applicable <strong>in</strong> our situation (although<br />
it is possible to estimate posterior AIC and BIC distributions based on the draws from the posterior<br />
and compare those across different mo<strong>de</strong>ls). Our preferred <strong>in</strong><strong>de</strong>x for mo<strong>de</strong>l selection is the<br />
Deviance In<strong>format</strong>ion Criterion (DIC; Spiegelhalter, Best, Carl<strong>in</strong>, & Van <strong>de</strong>r L<strong>in</strong><strong>de</strong>, 2002), which is<br />
easier to compute than Bayes factors, yet is a sufficiently theoretically sound measure for mo<strong>de</strong>l<br />
selection <strong>in</strong> a Bayesian framework. The DIC is calculated as a compromise between mo<strong>de</strong>l fit and<br />
the number of effective parameters of the mo<strong>de</strong>l (<strong>in</strong> the same spirit as the more traditional mo<strong>de</strong>l<br />
selection methods such as AIC or BIC), and is <strong>de</strong>f<strong>in</strong>ed as<br />
DIC = D( ) + pD<br />
ϑ , (9)<br />
where D( ϑ ) is the posterior mean of the <strong>de</strong>viance, used to measure mo<strong>de</strong>l fit, and,<br />
p<br />
D<br />
is an<br />
estimate of the effective number of parameters. Lower values of the criterion <strong>in</strong>dicate better fitt<strong>in</strong>g<br />
mo<strong>de</strong>ls (for more <strong>de</strong>tails, see Spiegelhalter et al., 2002).
Double-Sructure SEM 21<br />
After a mo<strong>de</strong>l is selected, it is recommen<strong>de</strong>d that the researcher evaluates the mo<strong>de</strong>l's global<br />
fit to the data. For this purpose we use samples from the posterior distribution via posterior<br />
predictive checks (PPC) (e.g., Gelman et al., 2003). The ma<strong>in</strong> i<strong>de</strong>a beh<strong>in</strong>d PPC is that “if the mo<strong>de</strong>l<br />
fits, then replicated data generated un<strong>de</strong>r the mo<strong>de</strong>l should look similar to observed data” (Gelman<br />
et al., 2003, p.165). In addition, a test quantity or discrepancy measure T ( y,<br />
ϑ ), which is calculated<br />
on the data and may <strong>de</strong>pend on the mo<strong>de</strong>l parameters, may be used to measure the discrepancy<br />
between specific features of the mo<strong>de</strong>l and data. When the test quantity T ( ⋅,⋅ ) does not <strong>de</strong>pend on<br />
the mo<strong>de</strong>l parameters, then it is called a test statistic and it is <strong>de</strong>noted by<br />
T ( y)<br />
. In this case, lack of fit<br />
can be assessed by the tail-area probability or<br />
p -value of the test quantity. Note that the PPC<br />
procedure allows one to choose any test quantity to check a particular relevant aspect of the mo<strong>de</strong>l.<br />
In practice, given a discrepancy measure, T ( y,<br />
ϑ ), the posterior predictive check<br />
p -value is<br />
calculated as follows:<br />
( k )<br />
1. Draw a vector ϑ from the posterior distribution.<br />
( )<br />
2. Simulate a replicated data set<br />
k<br />
( k )<br />
y from f ( y | ).<br />
rep ϑ<br />
( k )<br />
( k ) ( k )<br />
3. Calculate T ( y,<br />
ϑ ) and T ( y , )<br />
rep ϑ<br />
4. Repeat 1 to 3 K times.<br />
( )<br />
5. To obta<strong>in</strong> the posterior p -value, count the proportion of replicated data sets y k<br />
for<br />
rep<br />
( ) ( ) ( )<br />
which T( y k , ϑ k ) ≥ T(<br />
y,<br />
ϑ k ).<br />
rep<br />
Note that when a test statistic<br />
T ( y)<br />
is used, step 3 does not require a mo<strong>de</strong>l estimation at each<br />
iteration k , but only the calculation of T ( y)<br />
, and<br />
( k )<br />
T ( y ) for each replicated data set. Details of the<br />
rep<br />
implementation of PPC <strong>in</strong> W<strong>in</strong>BUGS are given <strong>in</strong> the R/W<strong>in</strong>BUGS supplementary material onl<strong>in</strong>e.<br />
Another useful tool for assess<strong>in</strong>g mo<strong>de</strong>l fit is the graphical display. In the case of discrepancy<br />
( k ) ( k )<br />
( k )<br />
measures, one can plot T ( y , ϑ ) and T ( y,<br />
ϑ ) aga<strong>in</strong>st each other. In the case of test statistics<br />
rep<br />
(1) ( K )<br />
one can compare T ( y)<br />
with T ( y ),…T<br />
, ( y ) by localiz<strong>in</strong>g T ( y)<br />
<strong>in</strong> the frequency distribution of<br />
rep<br />
rep
Double-Sructure SEM 22<br />
T ). In the application section of this paper we will use both a test quantity to check a particular<br />
( y rep<br />
aspect of our mo<strong>de</strong>l, and a global goodness-of-fit discrepancy measure.<br />
Application 1<br />
Mo<strong>de</strong>l<br />
Six mo<strong>de</strong>ls were fitted to the data. For convenience of notation, we represent frustration,<br />
antagonistic action ten<strong>de</strong>ncy, irritation, and anger with <strong>in</strong>dices 1, 2, 3, and 4, respectively.<br />
The six mo<strong>de</strong>ls have the same measurement mo<strong>de</strong>l but differ structurally. In general, the equations<br />
can be written as<br />
and<br />
PER SIT<br />
logit( π<br />
prs<br />
) = ηpr + ηsr + τr<br />
Measurement mo<strong>de</strong>l<br />
η = PER η + ζ Structural mo<strong>de</strong>l<br />
PER PER PER<br />
p B p p<br />
η<br />
= +<br />
SIT SIT SIT SIT<br />
s B ηs ζs<br />
(10)<br />
(11)<br />
with p = 1, …, 679, r = 1, …, 4 , and s = 1, …,<br />
11. Given that the hypothesized latent variables are<br />
response specific (four latent variables, one for each emotion response), it seemed reasonable to<br />
adopt a strong hypothesis, stat<strong>in</strong>g that each latent variable plays a role <strong>in</strong> only one k<strong>in</strong>d of emotion<br />
response. Un<strong>de</strong>r this hypothesis, the factor-load<strong>in</strong>g matrices <strong>in</strong> the measurement mo<strong>de</strong>l do not<br />
PER<br />
SIT<br />
conta<strong>in</strong> any free parameters, which is why λ<br />
rq<br />
and λ<br />
st<br />
from Equation 1 are no longer nee<strong>de</strong>d <strong>in</strong><br />
Equations 10 and 11. For every response, there is a s<strong>in</strong>gle latent variable on the person si<strong>de</strong>, and a<br />
PER<br />
separate one on the situation si<strong>de</strong>, so that, <strong>in</strong> Equation 1, λ = 1 when r = q and 0 otherwise,<br />
SIT<br />
and, correspond<strong>in</strong>gly, λ = 1 when r = t, and 0 otherwise, with Q = T = 4 .<br />
rt<br />
rq<br />
1<br />
The data and the R-W<strong>in</strong>BUGS co<strong>de</strong> used <strong>in</strong> this section are available at the <strong>APA</strong> website.
Double-Sructure SEM 23<br />
The six structural mo<strong>de</strong>ls are most clear when shown by graphical representations. Figure 4<br />
displays the path diagrams for three of the mo<strong>de</strong>ls (the rema<strong>in</strong><strong>in</strong>g three mo<strong>de</strong>ls are <strong>de</strong>rived from<br />
these). Mo<strong>de</strong>l 1 (with parallel and crossed effects) is the most general of the mo<strong>de</strong>ls; the latent<br />
response variables, irritation and anger, are each <strong>de</strong>term<strong>in</strong>ed by both of the latent explanatory<br />
variables: frustration and antagonistic ten<strong>de</strong>ncy. Mo<strong>de</strong>l 2 (with parallel effects) is the extreme form<br />
of the hypothesis mentioned earlier, stat<strong>in</strong>g that irritation is based only on frustration, and anger<br />
results solely from antagonistic action ten<strong>de</strong>ncy. Mo<strong>de</strong>l 3 (with only crossed effects) is the opposite<br />
of Mo<strong>de</strong>l 2, with irritation based exclusively on action ten<strong>de</strong>ncy and anger result<strong>in</strong>g only from<br />
PER<br />
SIT<br />
frustration. The correspond<strong>in</strong>g parameter matrices B and B of the three structural mo<strong>de</strong>ls are<br />
shown <strong>in</strong> Table 3. The three rema<strong>in</strong><strong>in</strong>g mo<strong>de</strong>ls are constructed by restrict<strong>in</strong>g the parameter matrices<br />
PER SIT<br />
of the person and situation si<strong>de</strong> to be equal ( B = B ). These mo<strong>de</strong>ls will be <strong>de</strong>noted as Mo<strong>de</strong>ls<br />
4, 5 and 6, respectively.<br />
PER<br />
PER<br />
SIT<br />
SIT<br />
F<strong>in</strong>ally, as stated earlier, it is assumed that ζ ∼ N ( 0,<br />
), and .<br />
p Ψ ζs ∼ N ( 0,<br />
Ψ )<br />
Because we are <strong>in</strong>terested <strong>in</strong> a complete explanation of the third and fourth latent variables, the<br />
PER<br />
covariances between ζ<br />
p3<br />
,<br />
PER<br />
ζ<br />
p3<br />
and<br />
PER<br />
ζ<br />
p4<br />
, and of<br />
PER<br />
ζ<br />
p4<br />
,<br />
SIT<br />
ζ<br />
s3<br />
and<br />
SIT<br />
ζ<br />
s3<br />
, and<br />
SIT<br />
s4<br />
SIT<br />
ζ<br />
s4<br />
are all set to zero. In addition, the variances of<br />
PER PER PER<br />
ζ , are constra<strong>in</strong>ed to be equal ( ψ = ψ = ψ , and<br />
ζ ζ ζ<br />
3 4<br />
ψ = ψ = ψ ). A mo<strong>de</strong>l allow<strong>in</strong>g different variances was also estimated, but this did not result<br />
SIT SIT SIT<br />
ζ 3 ζ4<br />
ζ<br />
<strong>in</strong> a better fit. Table 4 shows the<br />
Ψ<br />
matrices for the fitted mo<strong>de</strong>ls. Note that, because of the zero<br />
correlations among the residuals, the mo<strong>de</strong>l is not a saturated SEM.<br />
Estimation and mo<strong>de</strong>l selection<br />
A reparametrization of the mo<strong>de</strong>l was used with hierarchical center<strong>in</strong>g (e.g., Gelfand, Sahu,<br />
& Carl<strong>in</strong>, 1995; W.J. Browne, 2004) <strong>in</strong> or<strong>de</strong>r to avoid poor mix<strong>in</strong>g with<strong>in</strong> cha<strong>in</strong>s. Five cha<strong>in</strong>s were<br />
run start<strong>in</strong>g from different randomly selected <strong>in</strong>itial values for the parameters of <strong>in</strong>terest <strong>in</strong> each of
Double-Sructure SEM 24<br />
the fitted mo<strong>de</strong>ls. This approach helps the researcher monitor convergence and choose an<br />
appropriate burn-<strong>in</strong> period. Each cha<strong>in</strong> was run with 5000 iterations, and the first half of each cha<strong>in</strong><br />
was discar<strong>de</strong>d as a burn-<strong>in</strong> stage. For the <strong>in</strong>ferences and mo<strong>de</strong>l check<strong>in</strong>g we accepted every fifth<br />
draw of the rema<strong>in</strong><strong>in</strong>g 2500 draws of each of the five cha<strong>in</strong>s. Us<strong>in</strong>g non-consecutive draws helps<br />
reduce autocorrelation and avoid <strong>de</strong>pen<strong>de</strong>nce between subsequent draws. Thus, the results that are<br />
reported are based on a f<strong>in</strong>al sample of 2500 iterations.<br />
The R (Gelman & Rub<strong>in</strong>, 1992) was used to assess convergence. Values of R near 1.0 (say,<br />
below 1.1) are consi<strong>de</strong>red acceptable (Gelman et al., 2003, pp. 296-297). Also, graphical tools<br />
implemented <strong>in</strong> CODA were used to check the mix<strong>in</strong>g and autocorrelation of the cha<strong>in</strong>s. The R <br />
statistic for all of the parameters was less than or equal to 1.03 for all fitted mo<strong>de</strong>ls so we conclu<strong>de</strong>d<br />
that convergence had been established.<br />
Table 5 shows the obta<strong>in</strong>ed DIC values for the fitted mo<strong>de</strong>ls. From these results, it is clear<br />
that Mo<strong>de</strong>ls 1 and 4 are the preferred mo<strong>de</strong>ls. The mo<strong>de</strong>l with the lowest DIC was Mo<strong>de</strong>l 4, <strong>in</strong><br />
which the person and situation structure are restricted to be equal, both qualitatively and<br />
quantitatively. It must be noted, however, that, between Mo<strong>de</strong>ls 1 and 4, the difference <strong>in</strong> DIC<br />
values seems to be relatively small.<br />
Mo<strong>de</strong>l check<strong>in</strong>g<br />
Two types of tests were used to assess mo<strong>de</strong>l a<strong>de</strong>quacy. The first test was done to evaluate a<br />
particular aspect of our mo<strong>de</strong>l; that is, given that our ma<strong>in</strong> goal was to evaluate the correlational<br />
structure of the four traits (frustration, antagonistic action ten<strong>de</strong>ncy, irritation, and anger), the<br />
correlations between the sum scores over persons, Corr( y<br />
rs, y<br />
r′<br />
s<br />
), and over situations,<br />
+ +<br />
Corr y , y ′ ) for each construct ( r = 1, …, 4) were used as test statistics. The second test, an<br />
( pr+ pr +
Double-Sructure SEM 25<br />
2<br />
omnibus goodness-of-fit statistic, is the χ discrepancy measure (Gelman et al., 2003). In the<br />
2<br />
context of this application, the Pearson χ measure is <strong>de</strong>f<strong>in</strong>ed as<br />
2<br />
χ ( y ϑ)<br />
P R S<br />
, =∑∑∑<br />
( y − E( y | ϑ<br />
prs<br />
Var( y | ϑ)<br />
p= 1 r= 1 s=<br />
1<br />
prs<br />
prs<br />
2<br />
))<br />
. (12)<br />
The estimated p -values for correlations between the<br />
y + rs<br />
varied between 0.25 and 0.52 with<br />
a median of 0.36, and the estimated p -values for the correlations over the<br />
y<br />
pr +<br />
, varied between<br />
0.08 and 0.97 with a median of 0.84. A reasonable range for the p -value is consi<strong>de</strong>red to be the<br />
<strong>in</strong>terval between 0.05 and 0.95 (Gelman et al., 2003); based on this, we conclu<strong>de</strong>d that the mo<strong>de</strong>l fits<br />
the data. The more extreme p -values obta<strong>in</strong>ed when us<strong>in</strong>g correlations for are a consequence<br />
of the smaller number of situations consi<strong>de</strong>red.<br />
2<br />
Figure 5 shows a scatter plot of the χ test quantity evaluated for observed and replicated<br />
y<br />
pr +<br />
data. The posterior<br />
p -value (0.70) reported <strong>in</strong> the figure is calculated as the proportion of po<strong>in</strong>ts<br />
above the diagonal l<strong>in</strong>e (i.e., the proportion of replicated values that are larger than the observed<br />
ones). From Figure 5 it can be conclu<strong>de</strong>d that the mo<strong>de</strong>l fits the data reasonably well <strong>in</strong> a global way,<br />
as well.<br />
Results<br />
Table 6 shows the posterior means and standard <strong>de</strong>viations of the parameters <strong>in</strong> Mo<strong>de</strong>l 4<br />
and Figure 6 conta<strong>in</strong>s the graphical representation of the structural part of Mo<strong>de</strong>l 4, <strong>in</strong>clud<strong>in</strong>g the<br />
parameter estimates. In latent person and latent situation structures, frustration and the antagonistic<br />
action ten<strong>de</strong>ncy affect both irritation and anger. As expected, the feel<strong>in</strong>g of frustration is more<br />
important for irritation than the antagonistic ten<strong>de</strong>ncy, while the opposite is true <strong>in</strong> the case of<br />
anger. In the case of irritation, the difference is very small (0.49 versus 0.46); but for anger it is much
Double-Sructure SEM 26<br />
larger (0.54 versus 0.30). The correlation between the explanatory latent person variables is<br />
mo<strong>de</strong>rately high and positive (0.68), while the correlation between the explanatory latent situation<br />
variables is much lower, but still positive (0.25). The posterior standard <strong>de</strong>viation for correlation on<br />
the situation si<strong>de</strong> is larger than the one on the person si<strong>de</strong> due to the smaller sample of situations.<br />
The difference <strong>in</strong> correlations can be expla<strong>in</strong>ed by the difference <strong>in</strong> variance; the situations seem<br />
much more homogeneous than the persons. This difference <strong>in</strong> correlations is also <strong>in</strong> agreement with<br />
earlier f<strong>in</strong>d<strong>in</strong>gs (Vansteelandt et al., 2005; Zelenski & Larsen, 2000).<br />
The τ parameters must be <strong>in</strong>terpreted as <strong>in</strong>dicat<strong>in</strong>g the probability of show<strong>in</strong>g each of the<br />
four responses when all latent variables are set to zero (on the logistic scale). For <strong>in</strong>stance, for an<br />
average person <strong>in</strong> an average situation, the probabilities of endors<strong>in</strong>g responses 1 and<br />
6) equal:<br />
2<br />
(see Table<br />
exp(1. 56) exp(1.<br />
51)<br />
π<br />
p1s= = 083 . , and π<br />
p2s= = 082 . , (13)<br />
1+ exp(1. 56) 1+ exp(1.<br />
51)<br />
respectively. The two responses are approximately equally likely.<br />
The primary hypotheses of the study were confirmed by the analyses. The questions<br />
mentioned <strong>in</strong> the second section of this paper can now be answered <strong>in</strong> the follow<strong>in</strong>g way: Regard<strong>in</strong>g<br />
Question 1, based on the<br />
PER<br />
B<br />
matrix, we conclu<strong>de</strong> that irritation seems to be slightly more feel<strong>in</strong>g<br />
based but the difference is negligible, whereas anger is clearly more action based. Regard<strong>in</strong>g<br />
Question 2, which <strong>de</strong>als with situational structure, <strong>in</strong> this particular case, our conclusions match<br />
those stated for the person si<strong>de</strong>, because the best fitted mo<strong>de</strong>l was the one <strong>in</strong> which<br />
PER<br />
B<br />
and<br />
SIT<br />
B<br />
matrices were assumed to be equal. Regard<strong>in</strong>g Question 3, our conclusion is that the equality of the<br />
structures <strong>in</strong>dividual and situational differences was not contradicted by the data.
Double-Sructure SEM 27<br />
Discussion and Conclusion<br />
An extension of the regular SEM, called double-structure structural equation mo<strong>de</strong>l<br />
(2sSEM), was presented and shown to be useful for study<strong>in</strong>g un<strong>de</strong>rly<strong>in</strong>g structures <strong>in</strong> two mo<strong>de</strong>s of<br />
a three-mo<strong>de</strong> data set. A study of emotions, us<strong>in</strong>g a persons by situations by responses three-mo<strong>de</strong><br />
data set, was used to <strong>de</strong>monstrate how the mo<strong>de</strong>l can be utilized to assess <strong>in</strong>dividual differences and<br />
situational differences simultaneously, without the need to use two separate, unrelated mo<strong>de</strong>ls. Us<strong>in</strong>g<br />
a common mo<strong>de</strong>l for both structures can be advantageous <strong>in</strong> the sense that no <strong>in</strong><strong>format</strong>ion is lost.<br />
Unlike other mo<strong>de</strong>ls for three-mo<strong>de</strong> data, the 2sSEM treats two of the three mo<strong>de</strong>s as<br />
random. The 2sSEM may be also consi<strong>de</strong>red as a variant of a double-structure confirmatory factor<br />
analysis mo<strong>de</strong>l (2sCFA), however, <strong>in</strong> the CFA mo<strong>de</strong>l, correlations among latent variables can be<br />
assessed, but latent variables are never regressed on other latent variables. The 2sSEM adds a feature<br />
to the CFA mo<strong>de</strong>l by impos<strong>in</strong>g restrictions on how latent variables may affect each other. In the<br />
present application, there is only one latent (person, situation) variable for each response mo<strong>de</strong>, and,<br />
as a result, the 2sSEM looks like a path mo<strong>de</strong>l. Each element of the response mo<strong>de</strong> (anger, irritation,<br />
etc.) is, <strong>in</strong> fact, associated with a person x situation matrix rather than just the s<strong>in</strong>gle observed<br />
variable. In other applications, fewer latent variables may be nee<strong>de</strong>d, <strong>in</strong> which case, the results would<br />
look more like the standard SEM.<br />
A special feature of the data we consi<strong>de</strong>red is that they are b<strong>in</strong>ary. Thus, the mo<strong>de</strong>l<br />
<strong>de</strong>veloped here is an extension of a nonl<strong>in</strong>ear mixed mo<strong>de</strong>l for b<strong>in</strong>ary data. However, the mo<strong>de</strong>l can<br />
easily be adapted for cont<strong>in</strong>uous, or<strong>de</strong>red-category (rat<strong>in</strong>g-scale), or count data. In fact, the<br />
explanation of the mo<strong>de</strong>l was fairly general and oriented towards cont<strong>in</strong>uous data. The use of b<strong>in</strong>ary<br />
data for our example illustrates the generality of the mo<strong>de</strong>l. In addition, as a consequence of the way<br />
the 2sSEM is estimated here (via Bayesian methodology), miss<strong>in</strong>g data can be easily accommodated,<br />
as long as the miss<strong>in</strong>gness mechanism is ignorable (see Little & Rub<strong>in</strong>, 2002).
Double-Sructure SEM 28<br />
In this paper, the focus is on a data set of a particular k<strong>in</strong>d: a fully crossed three-dimensional<br />
data array with b<strong>in</strong>ary data on persons, situations, and emotional responses. An important asset of<br />
such data is that a comb<strong>in</strong>ation of two approaches is possible, one based on <strong>in</strong>dividual differences<br />
and another based on situation differences. Often the study of emotions is either based on the<br />
structure of <strong>in</strong>dividual differences, and correlations relat<strong>in</strong>g to these differences; or experimental<br />
methods, which only measure effects of situational differences. With three-mo<strong>de</strong> data and the<br />
2sSEM, it is possible to comb<strong>in</strong>e the two perspectives <strong>in</strong>to a s<strong>in</strong>gle analysis of <strong>in</strong>dividual differences<br />
and differences based on circumstances, situations, conditions, etc.<br />
Note that the number of situations is rather low <strong>in</strong> the application. As a consequence, the<br />
standard errors of the parameter estimates for the situation structure are larger than for the person<br />
structure when the scale is comparable, as can be seen <strong>in</strong> the large values of the standard error of the<br />
correlation between ζ 1 and ζ 2 ( see Table 6). However, the low number of 11 is still sufficiently high,<br />
<strong>in</strong> or<strong>de</strong>r for the regression parameters <strong>in</strong> the situation structure to be significantly different from<br />
zero <strong>in</strong> the case no equality constra<strong>in</strong>ts are imposed. Mo<strong>de</strong>l 1 is a mo<strong>de</strong>l without such constra<strong>in</strong>ts,<br />
Mo<strong>de</strong>l 4 is the equivalent with equality constra<strong>in</strong>ts. The number of situations will always be rather<br />
small, although perhaps larger than <strong>in</strong> the application, because this number is a multiplicative factor<br />
for the number of items.<br />
Latent variable mo<strong>de</strong>l<strong>in</strong>g <strong>in</strong> psychology is exclusively l<strong>in</strong>ked with <strong>in</strong>dividual differences. This<br />
is attributed, by Borsboom, Mellenbergh, and Heer<strong>de</strong>n (2002), “to a century of operat<strong>in</strong>g on silent<br />
uniformity-of-nature assumptions by focus<strong>in</strong>g almost exclusively on between-subjects mo<strong>de</strong>ls” (p.<br />
215), by which they mean that the latent variable mo<strong>de</strong>l based on <strong>in</strong>dividual differences is also<br />
assumed to apply with<strong>in</strong> persons. For example, <strong>in</strong> SEM approaches, often causal, between-persons<br />
effects are mo<strong>de</strong>led, and then generalized to with<strong>in</strong>–persons changes. Look<strong>in</strong>g with<strong>in</strong> persons can<br />
mean look<strong>in</strong>g at moments <strong>in</strong> time, as Borsboom et al. (2002) suggest, or across situations, as <strong>in</strong> the
Double-Sructure SEM 29<br />
present example. If the relations of latent person variables also apply to latent situation variables,<br />
then we have tested the validity of generaliz<strong>in</strong>g from between persons to with<strong>in</strong> persons. In other<br />
words, if the 2sSEM fits the data, and the structure of the person si<strong>de</strong> is the same as the structure of<br />
the situation si<strong>de</strong>, as was the case <strong>in</strong> the analyses presented here, then this type of generalization is<br />
supported. There are two other possibilities: First, the structure could be different for persons versus<br />
situations. The results of the 2sSEM can show whether this is the case, and if it is, the mo<strong>de</strong>l would<br />
still be valid. Second, the latent situation variables might differ across persons. In this case, the<br />
2sSEM approach would not be appropriate, because a basic assumption of the mo<strong>de</strong>l is that the<br />
persons are all alike with respect to the situational latent variables. However, apply<strong>in</strong>g the 2sSEM<br />
and test<strong>in</strong>g its goodness of fit provi<strong>de</strong>s way to assess the validity of this assumption.<br />
Other k<strong>in</strong>ds of three-mo<strong>de</strong> data can be imag<strong>in</strong>ed. For <strong>in</strong>stance, suppose that a sample of<br />
persons has been asked to rate another sample of persons not on just one personality trait (as <strong>in</strong> one<br />
of the cases of Shrout & Fleiss, 1979), but on a set of trait terms. The items can be thought of as<br />
<strong>in</strong>dicators of latent variables. The structure of <strong>in</strong>dividual differences between the raters is not<br />
necessarily equal to the structure of the <strong>in</strong>dividual differences between the persons who were rated,<br />
even though both structures are based on the same personality items. One could even argue that the<br />
equality of the two structures is suspicious, s<strong>in</strong>ce that may <strong>in</strong>dicate that the former is a mere<br />
reflection of beliefs from the part of the raters. A more challeng<strong>in</strong>g data set is one <strong>in</strong> which the first<br />
mo<strong>de</strong> is a random set of persons; the second mo<strong>de</strong>, a set of responses; and the third mo<strong>de</strong>, po<strong>in</strong>ts <strong>in</strong><br />
time. In this case, an assumption of a random time mo<strong>de</strong> requires some thought. For a time mo<strong>de</strong> to<br />
be random, it must be assumed that the residuals at the different time po<strong>in</strong>ts are <strong>in</strong><strong>de</strong>pen<strong>de</strong>nt for a<br />
given response, but can be correlated between responses (for example, a larger residual for response<br />
1 at time po<strong>in</strong>t t is more likely to co-occur with a larger residual for response 2 at the same time
Double-Sructure SEM 30<br />
po<strong>in</strong>t). Additionally, one may assume more ref<strong>in</strong>ed structural relations between these with<strong>in</strong>-timepo<strong>in</strong>t<br />
residuals.<br />
The 2sSEM is a useful mo<strong>de</strong>l for comb<strong>in</strong><strong>in</strong>g and compar<strong>in</strong>g the structures of two mo<strong>de</strong>s <strong>in</strong><br />
terms of a third mo<strong>de</strong> with<strong>in</strong> a data set concern<strong>in</strong>g, for example, emotions, as <strong>in</strong> the application<br />
shown here, or personality, as <strong>in</strong> the application about which we speculated. However, a 2sSEM is<br />
not appropriate for all three-mo<strong>de</strong> data. For example, only two types of <strong>in</strong>teractions may be<br />
accounted for, as shown <strong>in</strong> Table 1. In our application, these were persons by responses and<br />
situations by responses. The roles of the three k<strong>in</strong>ds of entities may be changed, but if these two<br />
pairwise <strong>in</strong>teractions are mo<strong>de</strong>led, then it is not possible to <strong>in</strong>clu<strong>de</strong> the third <strong>in</strong>teraction—that of<br />
persons and situations. In other words, for this mo<strong>de</strong>l to be useful, the <strong>in</strong>troduction of two types of<br />
latent variables, one for each of two of the three mo<strong>de</strong>s, must be mean<strong>in</strong>gful.
Double-Sructure SEM 31<br />
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Double-Sructure SEM 36<br />
Appendix A<br />
Latent threshold formulation of the mo<strong>de</strong>l for analyz<strong>in</strong>g b<strong>in</strong>ary data<br />
The measurement part of the 2sSEM can handle both cont<strong>in</strong>uous and b<strong>in</strong>ary observed<br />
variables. To illustrate this, we will relate the observed<br />
y prs<br />
variables to a cont<strong>in</strong>uous latent response<br />
y ∗<br />
prs<br />
variable .<br />
Consi<strong>de</strong>r the follow<strong>in</strong>g l<strong>in</strong>ear regression mo<strong>de</strong>l for cont<strong>in</strong>uous response variable y ∗<br />
prs<br />
:<br />
where ν<br />
prs<br />
<br />
PER<br />
= λr<br />
η + λ<br />
PER<br />
p<br />
<br />
SIT<br />
r<br />
η<br />
SIT<br />
s<br />
y = ν + ε , (14)<br />
∗<br />
prs prs prs<br />
+ τ<br />
r<br />
is the bil<strong>in</strong>ear predictor used for the 2sSEM, and<br />
prs<br />
ε is an<br />
error term of mean zero. This mo<strong>de</strong>l can alternatively be <strong>de</strong>f<strong>in</strong>ed as<br />
∗<br />
Ey ( | ν ) = ν . (15)<br />
prs prs prs<br />
In the case of cont<strong>in</strong>uous responses, the latent response equals the observed response: yprs = y ∗<br />
prs<br />
.<br />
In the case of b<strong>in</strong>ary responses, the response variable is <strong>de</strong>f<strong>in</strong>ed by the follow<strong>in</strong>g threshold<br />
mo<strong>de</strong>l<br />
It follows that<br />
y<br />
prs<br />
∗<br />
⎧ 1, if yprs<br />
> 0<br />
= ⎨<br />
⎩0 , otherwise .<br />
(16)<br />
E( y | ν ) = Pr( y = 1| ν ) = π<br />
(17)<br />
prs prs prs prs prs<br />
∗<br />
= Pr( y > 0 | ν )<br />
prs<br />
prs<br />
= Pr( ν + ε > 0)<br />
prs<br />
prs<br />
= Pr( ε >− ν )<br />
prs<br />
= F( ν prs<br />
),<br />
prs<br />
where the last equality is due to the symmetry of the distribution function<br />
F<br />
of<br />
ε<br />
prs<br />
. Typically, F<br />
is chosen to be either the cumulative standard normal or logistic distributions. In this paper, the<br />
logistic distribution was assumed such that
Double-Sructure SEM 37<br />
⎛ π ⎞<br />
−1 prs<br />
<br />
PER PER<br />
<br />
SIT SIT<br />
F ( π<br />
prs<br />
) = log = logit( π<br />
prs<br />
) = ν<br />
prs<br />
= r p<br />
+ r s<br />
τ<br />
⎜<br />
r<br />
1−π<br />
⎟<br />
λ η λ η + , (18)<br />
⎝ prs ⎠<br />
−1<br />
x<br />
F ( x) = log = logit( x)<br />
is the l<strong>in</strong>k function.<br />
where ( )<br />
1−<br />
x
Double-Sructure SEM 38<br />
Appendix B<br />
Derivation of the posterior distribution<br />
Assum<strong>in</strong>g conditional <strong>in</strong><strong>de</strong>pen<strong>de</strong>nce, the likelihood function for b<strong>in</strong>ary data is written as<br />
where F( ν ) = π (see Appendix A).<br />
prs<br />
prs<br />
⎛<br />
⎜ P R S<br />
⎜<br />
⎜<br />
⎜∏∏∏<br />
⎜<br />
⎝ p= 1 r= 1 s=<br />
1<br />
prs<br />
f( y | ϑ) = F( ν ) [1 −F( ν )]<br />
prs<br />
y<br />
prs<br />
⎞<br />
⎟<br />
1−<br />
yprs<br />
⎟<br />
⎟<br />
⎟<br />
⎟<br />
⎠<br />
,<br />
(19)<br />
In or<strong>de</strong>r to have a sample of ϑ we need to specify prior distributions for all the <strong>in</strong>volved<br />
parameters. For the parameters <strong>in</strong><br />
,<br />
τ<br />
PER SIT<br />
B B , and , normal diffuse priors with mean zero and<br />
4<br />
PER<br />
SIT<br />
variance 10 were chosen. For the upper left block of the covariance matrices Ψ , and Ψ (i.e.,<br />
the variances and covariance of the latent explanatory variables), <strong>in</strong>verse-Wishart prior distributions<br />
with scale matrix<br />
3<br />
10 I and 2 <strong>de</strong>grees of freedom were chosen. For the variances of the latent<br />
residuals (i.e., the diagonal elements of the lower right block of the<br />
Ψ<br />
matrices), Inverse-Gamma<br />
distributions with both shape and scale parameters equal to<br />
, were chosen. F<strong>in</strong>ally, the<br />
distribution for the latent person and situation residuals are given by the mo<strong>de</strong>l assumptions and are<br />
PER<br />
SIT<br />
multivariate normal distributions with zero vector mean and covariance matrices Ψ , and Ψ ,<br />
respectively.<br />
Us<strong>in</strong>g the relation <strong>in</strong> (8), the posterior distribution is then given by the product of the<br />
likelihood <strong>in</strong> (19) and<br />
4<br />
10<br />
P<br />
S<br />
PER PER SIT<br />
( ϑ) = ∏ ( ζ ; 0, ) ( SIT ) ( PER ) ( SIT ) ( ) ( PER ) ( SIT )<br />
p Ψ ∏ ζ ; 0, × ×<br />
s Ψ B B τ Ψ Ψ<br />
p= 1 s=<br />
1<br />
f N N p p p p p<br />
where N ( Z; μΣ) , means that the random vector Z is distributed as a multivariate normal<br />
(20)<br />
distribution with vector mean μ and covariance matrix Σ . Note that <strong>in</strong><strong>de</strong>pen<strong>de</strong>nce of the priors is<br />
assumed.
Double-Sructure SEM 39<br />
Author Note<br />
Jorge González, Paul De Boeck, Francis Tuerl<strong>in</strong>ckx, Department of Psychology,<br />
K.U.Leuven, Belgium.<br />
The authors have been partly supported by the Fund for Scientific Research - Flan<strong>de</strong>rs<br />
(F.W.O.) Grant no. G.0148.04 and by the K.U.Leuven Research Council Grant no. GOA/2005/04.<br />
The fisrt author is now at Measurement Center MIDE UC, Pontificia Universidad Católica <strong>de</strong> Chile,<br />
Santiago, Chile. We want to thank Betsy Feldman, four anonymous reviewers, and the associate<br />
editor for their valuable help and suggestions concern<strong>in</strong>g the manuscript.<br />
Correspon<strong>de</strong>nce should be addressed to Jorge González, Centro <strong>de</strong> Medición MIDE UC,<br />
Pontificia Universidad Católica <strong>de</strong> Chile, Vicuña Mackenna 4860, Macul, Santiago, Chile. Tel.: +56 2<br />
3545433; fax: +56 2 3547192. e-mail: jagonzal@uc.cl
Double-Sructure SEM 40<br />
Table 1<br />
Three approaches for mo<strong>de</strong>l<strong>in</strong>g three-mo<strong>de</strong> data. Variables that <strong>in</strong>teract are grouped together <strong>in</strong>si<strong>de</strong> a set of brackets;<br />
variables that are <strong>in</strong><strong>de</strong>pen<strong>de</strong>nt of one another are placed <strong>in</strong> separate brackets. Note: P=persons, S=situations,<br />
R=responses.<br />
Tucker3 (a) Tucker3 (b) SEM-MTMM<br />
2sSEM<br />
Interactions<br />
[PSR] [PSR] [PS] [PR] [PR] [SR]<br />
Parameters<br />
-Persons fixed random random random<br />
-Situations fixed fixed fixed random<br />
-Responses fixed fixed fixed fixed<br />
Depen<strong>de</strong>nce structure<br />
-Depen<strong>de</strong>nt irrelevant pairs (S,R) pairs (S,R) R<br />
-In<strong>de</strong>pen<strong>de</strong>nt irrelevant P P non-overlapp<strong>in</strong>g pairs (P,S)
Double-Sructure SEM 41<br />
Table 2<br />
Summary <strong>de</strong>scriptions of of the situations used <strong>in</strong> the study.<br />
Situations<br />
You are blamed for someone else’s failures after a sports match<br />
A fellow stu<strong>de</strong>nt loses your notes, caus<strong>in</strong>g you to fail the exam<br />
A floppy disk hold<strong>in</strong>g an important school assignment is <strong>de</strong>stroyed by your computer<br />
Your sibl<strong>in</strong>g sneaks out when you both have to clean up the house<br />
Be<strong>in</strong>g a jobstu<strong>de</strong>nt yourself, an employee makes you do all his chores<br />
A fellow stu<strong>de</strong>nt fails to return your notes the day before an exam<br />
After work<strong>in</strong>g hard on an assignment, your teacher says it’s still not better than your previous work<br />
It’s hard to study when the neighbors make a lot of noise and it’s a hot day<br />
A friend lets you down on an appo<strong>in</strong>tment to go out with his/her friend<br />
You’re at a party, and someone tells you that a friend outsi<strong>de</strong> has smashed your bike<br />
You hear that a friend is spread<strong>in</strong>g gossip about you
Double-Sructure SEM 42<br />
Table 3<br />
Parameter matrices <strong>in</strong> the structural mo<strong>de</strong>l for the three 2sSEM estimated mo<strong>de</strong>ls.<br />
Mo<strong>de</strong>l 1 Mo<strong>de</strong>l 2 Mo<strong>de</strong>l 3<br />
⎛<br />
⎜<br />
⎜<br />
0 0 0 0⎞<br />
⎛ 0 0 0 0⎞<br />
⎛ 0 0 0 0⎞<br />
⎟<br />
0 0 0 0<br />
⎜<br />
⎟ ⎜<br />
⎟<br />
⎟ ⎜<br />
0 0 0 0<br />
⎟ ⎜<br />
0 0 0 0<br />
⎟<br />
PER<br />
PER<br />
0 0⎟<br />
⎜β1<br />
0 0 0⎟<br />
⎜ 0 β2<br />
0 0⎟<br />
⎟ ⎜<br />
PER ⎟ ⎜ PER<br />
⎟<br />
0 0⎠<br />
⎝ 0 β4<br />
0 0⎠<br />
⎝β3<br />
0 0 0⎠<br />
PER<br />
B PER<br />
⎜β<br />
PER<br />
1<br />
β2<br />
⎜ PER<br />
β<br />
PER<br />
3<br />
β4<br />
⎝<br />
⎛<br />
⎜<br />
⎜<br />
0 0 0 0⎞<br />
⎟<br />
0 0 0 0<br />
⎟<br />
0 0⎟<br />
⎟<br />
0 0⎠<br />
SIT<br />
B SIT<br />
⎜β<br />
SIT<br />
1<br />
β2<br />
⎜ SIT<br />
β<br />
SIT<br />
3<br />
β4<br />
⎝<br />
⎛ 0 0 0 0⎞<br />
⎜<br />
⎟<br />
⎜<br />
0 0 0 0<br />
⎟<br />
SIT<br />
⎜β1<br />
0 0 0⎟<br />
⎜<br />
SIT ⎟<br />
⎝ 0 β4<br />
0 0⎠<br />
⎛ 0 0 0 0⎞<br />
⎜<br />
⎟<br />
⎜<br />
0 0 0 0<br />
⎟<br />
SIT<br />
⎜ 0 β2<br />
0 0⎟<br />
⎜ PER<br />
⎟<br />
⎝β3<br />
0 0 0⎠
Double-Sructure SEM 43<br />
Table 4<br />
Covariance matrices <strong>in</strong> the structural mo<strong>de</strong>l for the three 2sSEM estimated mo<strong>de</strong>ls<br />
Persons<br />
Situations<br />
Ψ<br />
PER<br />
ψ<br />
⎜ψ<br />
⎜<br />
=<br />
ψ<br />
0 0<br />
⎛ PER PER<br />
⎞<br />
⎜ ζ1 ζ1,<br />
ζ<br />
⎟<br />
⎜<br />
2<br />
⎟<br />
⎜ PER<br />
⎟<br />
PER<br />
ζ<br />
0 0<br />
2 ζ<br />
ψ<br />
⎟<br />
, 1 ζ 2<br />
⎟<br />
⎜<br />
PER<br />
⎟<br />
⎜ 0 0 ψ<br />
ζ<br />
0 ⎟<br />
⎜<br />
3<br />
⎟<br />
⎜<br />
PER<br />
⎟<br />
⎜ 0 0 0 ψ<br />
ζ ⎟<br />
⎝<br />
4 ⎠<br />
Ψ<br />
SIT<br />
⎛<br />
⎜<br />
⎜<br />
⎜<br />
ψ<br />
⎜ψ<br />
⎜<br />
=<br />
⎜<br />
⎜<br />
⎜<br />
⎜<br />
⎜<br />
⎝<br />
ψ<br />
0 0<br />
SIT SIT<br />
⎞<br />
ζ1 ζ1,<br />
ζ<br />
⎟<br />
2<br />
⎟<br />
SIT<br />
⎟<br />
SIT<br />
ζ<br />
0 0<br />
2 ζ<br />
ψ<br />
⎟<br />
, 1 ζ 2<br />
⎟<br />
SIT ⎟<br />
0 0 ψ<br />
ζ<br />
0 ⎟<br />
3<br />
⎟<br />
SIT<br />
⎟<br />
0 0 0 ψ<br />
ζ ⎟<br />
4 ⎠
Double-Sructure SEM 44<br />
Table 5<br />
DIC and p D values for the three fitted mo<strong>de</strong>ls (lower values for DIC are preferable)<br />
DIC<br />
p<br />
D<br />
Mo<strong>de</strong>l 1 25211.80 1456.53<br />
Mo<strong>de</strong>l 2 25335.80 1440.09<br />
Mo<strong>de</strong>l 3 25424.60 1454.99<br />
Mo<strong>de</strong>l 4 25209.50 1451.83<br />
Mo<strong>de</strong>l 5 25337.80 1444.47<br />
Mo<strong>de</strong>l 6 25423.10 1457.20
Double-Sructure SEM 45<br />
Table 6<br />
Results for Mo<strong>de</strong>l 4<br />
Mo<strong>de</strong>l 4<br />
Regression parameters <strong>in</strong> the B matrices<br />
Value sd<br />
PER SIT<br />
β1 = β1<br />
0.49 0.04<br />
PER SIT<br />
β2 = β2<br />
0.46 0.05<br />
PER SIT<br />
β3 = β3<br />
0.30 0.04<br />
PER<br />
β<br />
SIT<br />
= β<br />
0.54 0.05<br />
4 4<br />
Response effect parameters <strong>in</strong> τ<br />
τ 1.56 0.26<br />
1<br />
τ 1.51 0.27<br />
2<br />
τ 0.46 0.11<br />
3<br />
τ 0.34 0.12<br />
4<br />
Covariance parameters <strong>in</strong> the Ψ matrices<br />
PER<br />
ψ 3.93 0.34<br />
ζ1<br />
PER<br />
ζ1 ζ 2<br />
PER<br />
ζ 2<br />
SIT<br />
ζ1<br />
SIT<br />
ζ1 ζ 2<br />
SIT<br />
ζ 2<br />
PER<br />
ζ1 ζ 2<br />
SIT<br />
ζ1 ζ 2<br />
PER PER<br />
ζ<br />
ψ<br />
3 ζ4<br />
SIT SIT<br />
ζ<br />
ψ<br />
3 ζ 4<br />
ψ ,<br />
2.19 0.20<br />
ψ 2.70 0.24<br />
ψ 0.66 0.36<br />
ψ ,<br />
0.17 0.27<br />
ψ 0.71 0.42<br />
ρ ,<br />
0.68 0.03<br />
ρ ,<br />
0.25 0.28<br />
ψ<br />
ψ<br />
= 0.51 0.06<br />
= 0.10 0.04
Double-Sructure SEM 46<br />
Figure Captions<br />
Figure 1. Three-mo<strong>de</strong> data. The observation y<br />
prs<br />
represents the response of person p to question r<br />
un<strong>de</strong>r situation s .<br />
Figure 2. Proportion of endorsements for each of the four responses: A Situation si<strong>de</strong> (data<br />
agreggated over persons), B Person si<strong>de</strong> (data aggregated over situations)<br />
Figure 3. Graphical representation of the research questions<br />
Figure 4. Three different mo<strong>de</strong>ls: (a) Mo<strong>de</strong>l 1 (parallel and crossed effects), (b) Mo<strong>de</strong>l 2 (parallel<br />
effects), (c) Mo<strong>de</strong>l 3 (crossed effects)<br />
2<br />
Figure 5. χ values for the observed verus the replicated data based on 2500 simulations from the<br />
posterior distribution of ( y ϑ )<br />
rep ,<br />
Figure 6. Results for Mo<strong>de</strong>l 4 (parallel and crossed effects, equal for person and situation latent<br />
variables)
Persons<br />
1<br />
:<br />
:<br />
p<br />
:<br />
:<br />
P<br />
y 111<br />
y p11<br />
y P 11<br />
y P r1<br />
y prs<br />
y P R1<br />
1.. .. .. .. .. r.. .. .. .. .. ..R<br />
Responses<br />
y P Rs<br />
y PRS<br />
Situations<br />
1.. .. .. ..s.. .. ..S
Proportion of endorsements: Situations<br />
Proportion of endorsements: Persons<br />
Frustration<br />
Anger<br />
Frustration<br />
Anger<br />
Frequency<br />
0 2 4 6<br />
0.5 0.6 0.7 0.8 0.9<br />
Proportions<br />
Proportions<br />
Antagonistic action<br />
Frequency<br />
0 2 4 6<br />
Frequency<br />
0 2 4 6<br />
0.5 0.6 0.7 0.8 0.9<br />
Irritation<br />
Frequency<br />
0 2 4 6<br />
Frequency<br />
0 100 250<br />
0.0 0.2 0.4 0.6 0.8 1.0<br />
Proportions<br />
Antagonistic action<br />
Frequency<br />
0 100 250<br />
Frequency<br />
0 100 250<br />
0.0 0.2 0.4 0.6 0.8 1.0<br />
Proportions<br />
Irritation<br />
Frequency<br />
0 100 250<br />
0.5 0.6 0.7 0.8 0.9<br />
0.5 0.6 0.7 0.8 0.9<br />
0.0 0.2 0.4 0.6 0.8 1.0<br />
0.0 0.2 0.4 0.6 0.8 1.0<br />
Proportions<br />
Proportions<br />
Proportions<br />
Proportions<br />
(a)<br />
(b)
Frustration<br />
b<br />
a<br />
Irritation<br />
c<br />
Antagonistic<br />
ten<strong>de</strong>ncy<br />
d<br />
Anger
ηp1<br />
PER<br />
β PER<br />
1<br />
ηp3<br />
PER<br />
ηp1<br />
PER<br />
β PER<br />
1<br />
ηp3<br />
PER<br />
ρ PER<br />
η 1 ,η 2<br />
<br />
β2<br />
PER β3 PER<br />
<br />
ηp2<br />
PER β4 PER<br />
<br />
ηp4<br />
PER<br />
ρ PER<br />
η 1 ,η 2<br />
ηp2<br />
PER<br />
β PER<br />
4<br />
ηp4<br />
PER<br />
ηs1<br />
SIT<br />
β SIT<br />
1<br />
ηs3<br />
SIT<br />
ηs1<br />
SIT<br />
β SIT<br />
1<br />
ηs3<br />
SIT<br />
ρ SIT<br />
η 1 ,η 2<br />
<br />
β2<br />
SIT β3 SIT<br />
β <br />
η SIT<br />
s2<br />
SIT 4<br />
ηs4<br />
SIT<br />
(a) Mo<strong>de</strong>l 1<br />
ρ SIT<br />
η 1 ,η 2<br />
β SIT<br />
ηs2<br />
SIT 4<br />
ηs4<br />
SIT<br />
(b) Mo<strong>de</strong>l2<br />
ηp1<br />
PER<br />
ηp3<br />
PER<br />
ρ PER<br />
η 1 ,η 2<br />
<br />
β2<br />
PER β3 PER<br />
<br />
ηp2<br />
PER ηp4<br />
PER<br />
ηs1<br />
SIT<br />
ηs3<br />
SIT<br />
ρ SIT<br />
η 1 ,η 2<br />
<br />
β2<br />
SIT β3 SIT<br />
<br />
ηs2<br />
SIT ηs4<br />
SIT<br />
(c) Mo<strong>de</strong>l 3
T(y rep , ϑ)<br />
28000 30000 32000 34000 36000<br />
p=0.70<br />
28000 30000 32000 34000 36000<br />
T(y, ϑ)
ηp1<br />
PER 0.49 ηp3<br />
PER<br />
<br />
0.68<br />
0.46 0.30<br />
<br />
ηp2<br />
PER 0.54 <br />
ηp4<br />
PER<br />
ηs1<br />
SIT 0.49 ηs3<br />
SIT<br />
<br />
0.25<br />
0.46 0.30<br />
<br />
ηs2<br />
SIT 0.54 ηs4<br />
SIT