The Demand-Control Model: Specific Demands ... - Study at UniSA

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274 de Jonge, Dollard, Dormann, Le Blanc, and HoutmanTable 1. Demographic Characteristics of the Five SubgroupsHealth Bank/ RetailCharacteristic care Transport Insurance trade Warehouse Significance testGender (% men) 29.3 94.2 59.2 61.7 88.1 χ 2 (4) = 497.03*Employment(% full-time) 26.3 96.7 83.5 82.0 94.5 χ 2 (4) = 692.03*Age (mean) 36.3 38.3 35.5 31.0 35.8 F(4, 2455) = 33.69*Work experience (mean) 6.2 8.2 7.6 5.3 8.8 F(4, 1960) = 15.18**p < .05.MeasuresWe used several demographic characteristics (i.e., gender, age, and employmentstatus) in order to control for their possible influence.In line with the DCM, we used four job characteristics as predictor variables;that is, psychological demands (workload), physical demands, emotionaldemands, and job control (see also, Hockey, 2000). In addition, to minimizebias and cognitive processing, the corresponding items were precisely defined,and were as neutral as possible with frequency-based response categories rangingfrom 1 (never) to5(always) (Frese & Zapf, 1988; Wall et al., 1996). Principalfactor analyses (PAF) with oblique rotation clearly showed four factors witheigenvalues ranging from 5.52 to 1.81.Workload was measured by an 8-item scale that includes both quantitativeand qualitative demanding aspects of the job, such as time pressure and highcomplexity (de Jonge, Landeweerd, & Nijhuis, 1993). An example item is: “Inthe unit where I work, work is carried out under pressure of time.”Physical demands were assessed by a 7-item scale (de Jonge, Mulder, &Nijhuis, 1999). The items measure aspects such as carrying heavy loads, constrainedstanding, stooping deeply, and carrying shoulder high. For instance, “Inmy work, I have to carry shoulder high for a long time.”Emotional demands were measured by a 4-item scale that contained itemsabout aggressive and awkward clients or patients, and social problems like humansuffering (cf. de Jonge et al., 1999). An example is: “In my work, I amconfronted with aggressive clients.”Job control was assessed by 10 items and measured the worker’s opportunitiesto determine multiple facets of task elements, like method of working,pace of work, work goals, amount of work, working hours, and work evaluation(de Jonge, 1995). For instance, “The opportunity that the work offers to determinethe method of working yourself.”The choice of the four well-being indicators was also guided by the DCM.That is, emotional exhaustion and psychosomatic health complaints reflect out-
Demand-Control Model275comes of the job strain hypothesis, whereas job satisfaction and job challengereflect outcomes of the active learning hypothesis.Emotional exhaustion was measured by means of four items of the Dutchversion of the Maslach Burnout Inventory (Schaufeli & van Dierendonck, 1993).This instrument is particularly suitable for use in human service work (Maslach,1998). The scale was scored on a 5-point scale, ranging from 1 (never) to5(always). An example item is: “I feel emotionally drained from my work.”Psychosomatic health complaints were measured by 10 specific items dealingwith all kinds of complaints (Dirken, 1969). This scale was scored on a 3-point scale: 1 (no), 2 (seldom),3(yes). For instance, “Are you troubled byheadaches in the last six months?”Job satisfaction was assessed by a single item (i.e., “I am satisfied withmy present job”) that was scored on a 5-point rating scale, ranging from 1(strongly disagree) to5(fully agree). A meta-analysis by Wanous, Reichers,and Hudy (1997) has shown that single-item measures are highly correlated withmulti-item job satisfaction scales. A global indicator of overall job satisfaction,therefore, seems to be a valid and economic measure of general job satisfaction(see also Scarpello & Campbell, 1983).Job challenge was also measured by one item in which the respondentswere asked how challenging their work is. This question was also answered ona 5-point scale, ranging from 1 (strongly disagree) to5(fully agree).Data AnalysisIn order to analyze the data from the five groups, we performed multisamplestructural equation modeling (LISREL 8; Jöreskog & Sörbom, 1993). In thisway, we were able to judge the fit of a postulated model as a whole, taking intoaccount all equations as well as all groups simultaneously. Furthermore, it ispossible to test empirically the hypothesized relationships against several conceivablealternatives.Each of the components in our research model was included in the structuralequation analyses as a latent variable. In other words, the covariance structuremodel was simplified by assuming that the observed and latent variablesare identical (each construct had only one operationalization). This was particularlytrue for job satisfaction and job challenge.First of all, gender (dummy variable), employment status (dummy variable),and age were introduced into the structural model as potential confounders.Therefore, they were labelled as exogenous variables, and all other variableswere labelled as endogenous variables (i.e., job characteristics and outcome variables).In addition, the DCM suggests interactions between job demands andjob control. Such relationships can be appropriately modelled by including two
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