This paper examines to what extent the Four Dimensional Symptoms Questionnaire (4DSQ) and the Burnout Assessment Tool (BAT) are able to distinguish four diagnostic groups (i.e., employees suffering from stress complaints, burnout, depressive episode and other adjustment disorders, respectively) in a group of 5,791 employees who reported sick with psychological complaints. The group with other adjustment disorders was poorly predicted and emerged as a heterogeneous ‘residual category’. The three other groups can be more clearly distinguished from each other, with each measurement instrument having its own specific contribution; the 4DSQ for depression and the BAT for burnout. Hence, both self-report complement each other and should thus be combined. The shortened 12-item version of the BAT can be used just as well as the longer 23-item version (download full article).