Where is (im)balance? Necessity and construction of evaluated cut-off points for effort-reward imbalance and overcommitment

The use of cut-off values is common in research on the effort-reward imbalance (ERI) model. They are often used to identify health risk situations or behaviour at work, although little is known about their diagnostic properties. The aim of the study was to investigate empirically cut-off points for the effort-reward ratio and the over-commitment (OC) scale. The study was based on a sample of 302 teachers. According to the International Classification of Mental and Behavioural Disorders-10 (ICD-10), 115 subjects suffered from a mood disorder. The control group consisted of 187 matched healthy subjects. Receiver-operating characteristic analyses were conducted using the ERI ratio and OC as diagnostic variables. A mood disorder served as gold standard reference test. Results demonstrated the ability of the effort-reward ratio and OC to discriminate between diseased and healthy individuals. However, a comparison of the areas under the curve revealed a significantly higher diagnostic power for the effort-reward ratio. According to the Youden index, optimal cut-off points were ERI > 0: 715 and OC > 16. Furthermore, sensitivity and specificity for different cut-off values are presented. Results point to shortcomings in the ERI literature using established approaches to define cut-off points. Validating cut-off values is of particular importance in order to ensure valid results in ERI research.