Three different methods were used to investigate the basis of judgments about the success of inclusion made by key staff in an education service in the UK. First, a structured questionnaire was used by staff to rate the pupil social and learning skills needed for success in mainstream classes. Second, an open-ended elicitation technique was used to identify criteria for successful inclusion that are spontaneously generated by staff. Third, a scenario rating scale was constructed to assess experimentally the relative priority accorded by staff to each success criterion. A substantial degree of consensus across methods was identified in the specific skills and key success criteria considered important by different groups of staff. Parallels with previous questionnaire-based research conducted in the US are discussed. Some differences across methods and respondent groups are also identified, and the potential advantages of multi-perspective, multi-method approaches to assessing inclusion success criteria are considered.