The aim of the research was to investigate the validity of a new procedure for assessing the communication skills of adult mentally handicapped people. At present there are no communication assessments designed for this client group. The procedure, known as the Communication Assessment Profile (CASP) was used with 202 adults selected from eight hospitals and 15 community placements. Results have shown that CASP is a reliable clinical tool, able to measure communication skills with accuracy, and sensitive to differences between adults living in hospital and community settings. This report provides a summary of the findings, the details of which are published elsewhere.