Study questions on examination literature
Work & Performance Course 2018-2019
De Lange, Taris, Kompier, Houtman & Bongers (2003)
De Lange, A.H., Taris, T.W., Kompier, M.A.J., Houtman, I.L.D., & Bongers, P.M. (2003). The very best
of the millennium: Longitudinal research and the Demand-Control-(Support) Model. Journal of
Occupational Health Psychology, 8, 282-305.
Abstract
This study addressed the methodological quality of longitudinal research examining R. Karasek and T.
Theorell’s (1990) demand-control-(support) model and reviewed the results of the best of this
research. Five criteria for evaluating methodological quality were used: type of design, length of time
lags, quality of measures, method of analysis, and nonresponse analysis. These criteria were applied
to 45 longitudinal studies, of which 19 (42%) obtained acceptable scores on all criteria. These high-
quality studies provided only modest support for the hypothesis that especially the combination of
high demands and low control results in high job strain. However, good evidence was found for
lagged causal effects of work characteristics, especially for self-reported health or well-being
outcomes. The following questions are central in this study:
1. How many longitudinal studies examining the DC/S model meet five important methodological
criteria and can therefore be labelled as high-quality studies?
2. What are the results of these high-quality longitudinal studies as regards the propositions
advanced in the DC/S model? Moreover, do these high-quality studies provide evidence for normal
(instead of reversed or reciprocal) “causal” relationships between Time 1 demands, control, or social
support and Time 2 health outcomes?
• Describe the Demand-Control Model and the Demand-Control-Support Model. These models
are not described in the article itself, but can be found in e.g. Peeters, De Jonge & Taris (2014),
chapter 3.
The key idea behind the job-demands-control model (JDC model) is that control buffers the impact of
job demands on strain and can help enhance employees’ job satisfaction with the opportunity to
engage in challenging tasks and learn new skills (Karasek, 1979). For a visual representation of the
demands-control model see figure 1. The job-demands control support model (JDCS model) adds
social support to the JDC model. Social support could also be a buffer the impact of job demands on
strain and can help enhance employees’ satisfaction with the job. The predictions of the DCS model
strongly resemble those of the DC model, assuming that the strain hypothesis of the DC model will
especially apply under conditions of low support. For a visual representation, see figure 2.
Figure 1: Job demands control model Figure 2: Job demands control support model
,• Explain the strain hypothesis and the iso-strain hypothesis (e.g. Using Peeters et al. (2014)).
Strain hypothesis: The combination of low demands and high job control (low-strain jobs) will lead to
will lead to a lower than average number of health complaints. The combination of high job demands
and low job control (high-strain jobs) is assumed to result in psychological stress reactions, such as
high blood pressure and low job satisfaction.
Iso-strain hypothesis: The combination of low demands, high job control and low social support will
lead to a decreased well-being.
• Explain the two main advantages of longitudinal research over cross-sectional research
according to De Lange et al. (2003).
Advantage 1: Cross-sectional research designs are ill-suited to test causal relationships, because they
cannot provide any evidence regarding the temporal order of the variables. Although statistical
techniques such as structural equation modeling (SEM) may provide an indication of the causal
direction of particular pathways in cross-sectional research, strong evidence on the causal order of
variables requires a longitudinal design.
Advantage 2: Cross-sectional research designs do not allow for examining reversed and reciprocal
causal relationships. In occupational health research it is often assumed that job characteristics (e.g.,
demands and control) influence health. Apart from these “standard” causal relationships,
longitudinal designs often offer the possibility to examine the effects of Time 1 health on (the
evaluation of) Time 2 job demands and control (reversed causal relationships. This also implies that
cross-sectional designs are ill-suited for exploring reciprocal causal relationships, in which variable X
(e.g., job characteristics) and Y (e.g., health) mutually influence each other. Such relationships should
be controlled for, as they may provide alternative explanations for certain associations between
variables.
• Explain when the strain hypothesis is supported according to De Lange et al. (2003).
With Karasek, we consider focusing on the multiplicative interaction only too narrow. We therefore
suggest that future research uses a broad definition of support of the DC/S model. In the present
article we propose that both additive (main effects only) or multiplicative interaction effects support
the strain hypothesis of the DC/S model, provided that workers in the high-demands/low-control
condition experience the highest levels of strain. More specifically, we consider the strain hypothesis
of the DC model supported when there are two main effects of job demands and job control and/or
when there is a multiplicative interaction effect between these two work characteristics (not in
combination with a third variable), such that employees working in environments characterized by
high demands and low control experience the highest level of strain. The strain hypothesis of the DCS
model is supported when the above-mentioned additive or multiplicative interaction effects of
demands and control are complemented with a main or interaction effect of social support (not in
combination with a fourth variable), such that employees working in environments characterized by
high demands, low control, and low social support experience the highest level of strain.
• Explain the difference between additive and multiplicative support of the strain hypothesis.
Additive support of the hypothesis are the main effects only, in this case job control and job demand.
Multiplicative support of the hypothesis are interaction effects: interaction between these two work
characteristics, job control and job demands (not in combination with a third variable).
,• De Lange et al. (2003) use five criteria to assess the quality of longitudinal studies based on the
DC/S model. Name three of these criteria. Explain in what way good or very good studies differ
from poorer studies with regard to these criteria.
The five criteria are:
1. Type of longitudinal design: The advantage of a complete panel design compared with
incomplete panel designs (in which not all study variables are measured on all time points) is
that these three types of causal relationships can be distinguished from each other, meaning
that a fuller understanding of the causal process can be obtained.
2. Length of the time lags between the waves of the study: A complete panel design is
insufficient to demonstrate causal effects over variables over time, because the researcher
still has to consider the length of the time lag that is needed to detect any effects. In the
absence of commonly accepted guidelines on the correct length of time lags, researchers
should discuss their choice for a particular time lag in the light of the question how the effect
of X on Y develops over time. Further, the choice for a particular time lag may also be based
on the wish to control for alternative explanations for associations between variables, such
as interim effects (i.e., effects of unobserved events during the time lag, such as a job
change), maturation effects (e.g., effects due to increased experience), and seasonal effects
(e.g., effects of measuring in summer or winter).
3. Quality of the measures: longitudinal research usually uses a survey design, which brings the
problem of self-report bias. The reliability of an instrument can be demonstrated by referring
to journal articles in which the quality of this instrument is established or by calculating a
reliability score (such as Cronbach’s alpha) for one’s own data. A study is considered
acceptable when it includes good references for and acceptable reliabilities of one’s variables
(alpha of around .70); it is very good if it includes an objective measure as well (e.g., a
psychophysiological measure), provided that this measure reflects a salient facet of the
employees’ experience.
4. Statistical analysis: Three main methods of statistical analysis were used: correlational
research (e.g., the comparison of cross-lagged correlations), multiple regression, and
structural equation modeling (SEM). In correlational research it is difficult to demonstrate
reversed or reciprocal causal relationships, as the cross-lagged correlations depend on the
variances of the measured variables and the across-time stability of the variables. Therefore,
multiple regression analysis and SEM are preferred for analyzing cross-lagged effects.
5. Nonresponse analysis: A study is considered acceptable when it examines possible selectivity
of the response on baseline and on the follow-up measurements (e.g., in terms of gender
and age); it is very good when it examines whether the associations at baseline between the
DC/S dimensions and the outcome variables differ for responders and non-responders (i.e.,
those who drop out of the study after baseline).
, • Use the relationship between workload and burnout to explain when a normal causal
relationship exists, when a reversed causal relationship exists and when a reciprocal causal
relationship exists.
Normal or standard causal relationships: X is causing changes in Y (hypothesized effects, for example
a higher workload causes a higher level of burnout.
Reversed causal relationships: Y is causing changes in X (the opposite of hypothesized effects), for
example a higher burnout causes a higher perceived workload.
Reciprocal causal relationship: X is causing changes in Y, and Y is causing changes in X, for example
workload and burnout mutually influence each other over time.
• De Lange et al. (2003) found 45 longitudinal studies in which the DC/S model is tested. They
selected 19 of these studies on the basis of quality criteria. Explain the advantages and
disadvantages of such a selection based on quality.
19 high-quality studies were identified, obtaining at least sufficient ratings on all criteria.
Advantages: this procedure maximizes the reliability of the results presented in the high-quality
studies.
Disadvantages: authors may feel attacked because of a bad rating.
• Naturally you do not have to memorise Table 4, but you do need to have a good understanding
of the table. Study what is contained in Table 4 for Dollard (1997). Describe the findings of
Dollard (1997) with regard to the DC/S model. For which independent variables is the model
confirmed and for which is it not confirmed? Do the same for Johnson et al. (1995).
Dollard (1997) recruited 104 workers (51 women, 53 men) from the general population (different
occupations). Dependent variables were physical health symptoms, work-home conflict and job
satisfaction. Outcomes variables are demand, control and support. ‘s’ means that it’s significant, so
only job satisfaction is significant. There are no main effects, as there is a cross-over interaction. DC
and DCS hypothesis are confirmed, but only for job satisfaction. The normal causation is positive and
the reversed causation is not examined.