This paper takes as its starting point an examination of the current status of some of the concerns that were raised in the mid-1980s about methodological problems faced by educational researchers using the behavioural approach in schools. These concerns included the measurement of agreement between observers, the interpretation of raw data extracted, the potential influences of observers and the inherent properties of research designs. Subsequently, some more wide-ranging concerns are considered, in particular the kinds of behaviour selected for treatment, the lack of analysis of what is involved in teachers' positive responses to pupils' behaviour and the relatively uninvestigated effects of teachers' negative responses. The conclusions are presented as a series of points that are listed, as far as possible, in the order in which they confront the investigator.