CONNECTIONS - INSNA

CONNECTIONS
Configurations of Homophily
elements of the power set). With five
sociodemographic dimensions there are 32
possible configurations. Given a large number
of individuals who are heterogeneous along
several dimensions, it is not surprising that all
configurations of homophily are represented.
The first row is the null set, absence of
homophily on all five dimensions. The most
common configuration is number 16, which
includes similarity on four of the five
dimensions (Sex, Race, Education, and
Religion). This configuration contains 27%
more relationships than the second most
frequent configuration (number 32), which is the
complete homophily configuration.
Configuration Frequency
To determine which configurations occur more
often than expected by chance it is necessary to
compare the observed number of relations in
each configuration to a baseline level that
represents random association. The theoretical
baseline population in this research comprises
all possible relations in the United States in
1985. Like many surveys of the general
population, the GSS underrepresents males
(Davis & Smith, 1996) and the marginal
distributions of other demographic dimensions
do not match U.S. population estimates. To
create a representative baseline, the data were
weighted to reflect the general population using
U.S. census estimates from 1985 to weight by
age, sex, and race and from 1990 to weight by
education (U.S. Census Bureau, 1990, 2000).
Respondents were not weighted by religion as
the GSS comprises the best available national
estimate of religious identification. Using the
GSS as the basis for computing the baseline,
rather than census estimates that don’t include
religion, has the advantage of preserving the
consolidation of parameters. Maintaining the
correlation of dimensions within individuals is
vital when examining how multiple dimensions
simultaneously draw people together. An
expected proportion was computed for every
configuration of homophily and can be seen in
the Baseline column of Table 1 (computation of
the baseline is presented in the Appendix).
Examination of Table 1 reveals that the
distribution of dyads across configurations
varies from that expected by chance. For
instance, the top row represents relations that are
different on all five dimensions. Examining the
“All” column we see that the 0.1% of dyads
observed in this configuration is well below the
3.1% expected by chance. Conversely, the
12.8% of dyads in the bottom row, homophily
on all dimensions, is well above the 1.6%
expected by chance. To evaluable how
dimensions interact to affect the frequency of
observed dyads, each configuration was coded
as exceeding the baseline frequency or not. This
was determined using a z-test for proportions
with an alpha of .05. Those configurations
whose proportion was significantly higher than
the baseline proportion were coded as 1;
otherwise they were coded as 0. Ten
configurations occurred more often than
expected by chance while twenty-two did not.
Role relations correspond to common foci that
bring people together and provide the
opportunity for relationships to develop
(Marsden, 1990). Examining role relations
independently can provide insight to the
multidimensional nature of homophily induced
through substructures. The GSS allowed
respondents to select multiple ways in which
they were connected to each alter. This research
utilizes the following relations: kin, coworkers,
friends, and group members. Since kin relations
evolve through a different process than most
other relations a distinction was made between
kin and nonkin. Relations with parents, siblings,
children, and other family members were
collapsed into the kin relation. To help ascertain
the homophily induced by substructural foci and
not pre-existing kin relations, only nonkin
friends, coworkers, and group members were
considered. Table 1 reports the distribution of
dyads across homophily configurations by type
of role relation. The proportion of dyads of each
relation type in each configuration was
compared to the baseline, with those exceeding
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