*5.1. Limitations*

Although this study is the first examining the relationship between cognitive demands and employee well-being based on a large data set representative for the German working population, there are some limitations that have to be acknowledged. First, the interpretation is limited due to the cross-sectional nature of the study. Thus, the analyses allow alternative explanations as we are not able to account for reverse causality or unobserved heterogeneity. Consequently, future research should elaborate on this, for example by replicating the analyses within a longitudinal study design. Second, all measures were based on self-reports from participants, raising the risk of overestimated results due to common method biases [58]. However, various authors point out that subjective views are certainly an important indicator of objective health-related outcomes [59]. Self-reports may not be too problematic when investigating interaction effects: Common method effects are likely attenuating rather than strengthening interactions [60]. Third, we used single items to measure cognitive demands. Although single item measures are found to be valid [55,61], studies and theories presented at the beginning of the paper suggest that cognitive demands might be a multi-dimensional concept on which future research should focus on. Finally, our analyses are based on the whole working population rendering knowledge on the relationship between cognitive demands and employee well-being in a general sense, which can be interpreted as a first step in discovering this issue. In order to better understand this relationship, future research should elaborate on the heterogeneity across groups, for example by performing subgroup analyses with respect to gender, age groups, and educational level, but also occupations. This is crucial in order to derive concrete recommendations for action.
