On cross-sectional questionnaire studies of relationships between psychosocial conditions at work and health—are they reliable?

Abstract

It is not known towhat extent self reported assessments of the psychosocial work environment—that the majority of research reports have been based upon—reflect individual characteristics (which may distort the perception of reality) and to what extent they reflect true environmental conditions. Critics argue that ‘‘subjectivity bias’’ may explain most of the observed associations between psychosocial working conditions and health (Wainwright and Calnan 2002; Mc Leod and Davey Smith 2003). This is indeed a classical problem in this research. We will discuss some aspects of this but the reader interested in the whole range of assessment problems is referred to other articles (for instance Zapf et al. 1996). The problem with self-reported data is particularly prominent when both psychosocial environment and health are described by means of self-reports (common method variance) and when both are recorded at the same time in a cross-sectional study. Such studies are relatively cheap and easy to perform and they are therefore abundant. The source of error that comes to mind first of all is a possible tendency among subjects who ‘‘complain about everything’’ to exaggerate problems in the environment as well as in their own health. This is frequently labelled negative affectivity (for discussion of negative affectivity in psychosocial research see Cooper 2000; Judge et al. 2000; Payne 2000; Spector et al. 2000). In the other end there are also subjects who complain about nothing and are therefore underreporting both environmental and health problems—denial. These two groups together could cause severe interpretation difficulties. They may cause inflated relationships in studies of representative working populations who include both participants with negative affectivity and with denial. In populations with a high proportion of denying participants spuriously small associations may be found (underestimation of risk). The opposite may be the case if negative affectivity is prominent (overestimation of risk). It should also be pointed out that both denial and exaggeration may be due to external pressures—for instance in work sites where employees want to get rid of a superior or in work sites where they are forced to conceal bad conditions and fear punishment if they complain. The next source of error that could cause problems is the fact that illness could cause secondary changes in psychosocial work environment—a long lasting illness may cause a subject to change jobs and for instance also to perceive increased demands or other changes in the psychosocial work environment. Illnesses, which have lasted for a long time, are particularly problematic from this point of view. It could be impossible to knowwhether the illness causes the environment or the environment causes the illness. A similar problem is that the duration of exposure may make a difference. If a cross-sectional study is based upon working conditions at one point of time and illness at the same time it is impossible to know whether the assessment of the exposure represents something that has been going on for many years or only for a couple of days. In chronic illness development this may be crucial. After a short exposure there may be no sufficient basis for illness development. Both of these problems represent the time dimension in the assessment.