Background: Teachers' work overload has been the subject of intense research, and the results of these studies show that a substantial proportion of teachers perceive their job as very stressful.
Aims: To investigate how different formulations of high demands and low decision latitude was related to teachers' burnout, and to estimate the possible interaction between these factors.
Sample: The sample consisted of 1,028 school teachers.
Method: Multivariate covariant analyses (MANCOVA) was used to evaluate the relationship between a high-strain job defined by 3 different cut-off points and burnout. Logistical regression analysis was used to estimate the separate and joint effects of demand and decision authority on emotional exhaustion. Interaction between high demands and low decision authority was analysed using relative excess risk due to interaction (RERI). An attributable proportion (AP) was calculated in order to estimate the proportion of emotionally exhausted teachers among those exposed to both risk factors that was attributable to their synergistic interaction. The group of teachers who perceived their job as a low-strain job was used as the reference group in the analysis.
Results: The effect of job strain on burnout was proved to be consistent and robust across alternative formulations. The main effect of high demands exceeded that of low decision authority in relation to emotional exhaustion. Furthermore, the 2 factors acted synergistically to increase the risk of burnout.
Conclusions: In the case of burnout, teachers who perceived their job as highly demanding and low in control, 69% of the effect could be attributed to the synergism of these 2 factors.