This paper describes the evaluation of a local authority behaviour support initiative that involved the re-location of four behaviour support teachers from pupil referral units into three mainstream secondary schools to work with pupils at risk of exclusion. The evaluation was largely illuminative (Parlett, 1981) and focused on the effect of changing off-site behaviour support to in-school support. The research approach taken incorporated a Co-operative Inquiry strand (Heron, 1996) where researchers and behaviour support teachers worked together to design major aspects of the research process. This enabled research outcomes to inform educational practice, and gave a reflective, formative aspect to the study. The overall approach to the design of the study was informed by the Research and Development in Organisations (RADIO) model developed by Knight and Timmins (1995). The application of this approach in the context of the study is described along with a brief account of the findings. Finally, brief comment is made on the way in which the RADIO approach might contribute to educational psychologists' work at the local education authority and whole school levels. (Contains 4 tables.)