This article shows the importance of paying attention to the role of professional devices, such as standardised forms, as producers of normality and deviance in the history of education. Our case study focused on the standardised forms used by teachers during child guidance clinic referrals and transfers to special education in northern Finland, from the 1950s to the early 1990s. How standardised forms were constructed and how they guided teachers through their evaluations had important consequences for the children's diagnoses. A close analysis of the contents and meanings of forms enabled us to assess how criteria for normal and problematic behaviours were defined, as well as to evaluate the underlying professional and institutional practices. During the period studied, the criteria set for "normal" and "deviant" behaviours changed surprisingly little. Children were perceived as psycho-physical organisms who respond to family-related problems, but school environments' effects, for example, were left unacknowledged. Problems were identified solely as originating within the individual children and their family. Teacher statement forms were used as a tool to ensure cooperation between the child guidance clinic and the compulsory school system. The forms invited the teachers to adopt a psychological approach to childhood development and established child guidance clinics as a leading expert in the process of selecting children for special education. Changes in the forms' structure reflected differences in perceptions concerning the boundaries of professional fields.