A temporal investigation of the direct, interactive, and reverse relations between demand and control and affective strain

Abstract

Few studies have tested how stressors affect outcomes over time. We sought to extend the literature by means of a longitudinal study testing for direct, interactive, and causal relations between demands and control and affective strain. We extended prior work testing causal relationships for Karasek's (1979) Job Demand-Control (JDC) model by examining both the effects of demands and control on strain and in turn the effects of strain on demand and control. We tested our hypotheses using hierarchical linear modelling with a military sample of 1539 soldiers who completed six waves of survey data at 3-month time lags. The results replicate earlier cross-sectional studies reporting effects of work characteristics on strain; however, in our study these effects did not persist past three months. The results also provide evidence for reverse causal effects such that higher strain was associated with higher subsequent work overload and lower control over a six month time period. Similar to past research, we did not find support for the interactive effects of work overload and control on strain. We discuss the implications of our findings for theory and practice (such as the optimum time for applying interventions during the management of change), especially in terms of understanding the specific time lags for different stress–strain associations and the need for additional theories to explain reverse relationships.

Keywords:

• occupational stress
• affective strain
• Job Demand-Control model
• longitudinal research
• military personnel

Acknowledgements

We would like to acknowledge COL Carl A. Castro as the principal investigator for the WRAIR protocol under which the data for this paper were collected. This research was conducted in partial fulfilment of the first author's dissertation at Portland State University. We thank Wayne W. Wakeland, Ph.D., Talya N. Bauer, Ph.D., and Alan Cabelly, Ph.D., for their assistance related to the preparation of this article. Research findings described in this paper were collected under WRAIR Research Protocol #700 entitled, “A Human Dimensions Assessment of the Impact of OPTEMPO on the Forward-Deployed soldier.”

An earlier version of this paper was presented at Work, Stress, and Health, New Challenges for a Changing Workplace. Conference sponsored by the American Psychological Association and the National Institute for Occupational Safety and Health, Miami, Florida, 2006. The views expressed in this paper are those of the authors and do not necessarily represent the official policy or position of the Department of Defense, US Army Medical Research and Materiel Command, or the US Army Research Institute.