Background: Observational measures of parent and child behaviours have a long history in child psychiatric and psychological intervention research, including the field of autism and developmental disability. We describe the development of the Standardised Observational Analogue Procedure (SOAP) for the assessment of parent-child behaviour before and after a structured parent training program for children with pervasive developmental disorders (PDD). We report on the use of this procedure in a pilot study of 12 participants with PDD. Results: Inter-rater reliability across behaviours coded ranged from 75-100% agreement. Blindly scored observations of behaviour showed medium effect sizes for changes in inappropriate child behaviour. Analyses of baseline scores revealed a moderate positive correlation between inappropriate child behaviours as measured in all four SOAP conditions and parent ratings of child noncompliance (r[subscript s] = 0.66, p less than 0.05). By contrast, the correlations of SOAP scores with parent ratings of irritability was lower (r[subscript s] = 0.40, p greater than 0.05). Conclusions: As our treatment targeted compliance, these preliminary results suggest that the SOAP provides a valid measure of noncompliant behaviour in children with PDD and is sensitive to treatment effects on inappropriate child behaviours. (Contains 3 tables.)