From the 1920s, children in Switzerland were psychiatrically examined in observation wards. In many cases, these medical reports were linked to the placement of children in homes and foster families. Focusing on a specific case study of the observation institution Stephansburg in Zurich in 1944, this paper retraces the genesis of a child psychiatric report, identifying patterns by which the experts dealt with narratives of teachers, parents or school doctors. At a closer look, tests and medical examinations were not necessarily committed to a strictly scientific approach. The case study analysed in this paper indicates that experts in child psychiatry did not always apply expert knowledge when preparing their opinion. Rather, they resorted to a selection of aspects alien to psychiatry but suitable to satisfy the interests of the contracting authority.