Clients with chronic back pain can benefit from learning strategies to manage their pain. In a 3-week pain management programme, the use of a videotaped assessment on admission and at discharge enables occupational therapists to score functional movement, as well as providing visual feedback for the clients, although evidence of reliability is necessary. This study investigated the reliability of intrarater and interrater scoring between four experienced occupational therapists who scored the video assessment. Forty clients and forty controls were chosen to complete the assessment. The assessment consists of tasks with 59 different items to score. Each task is scored on three factors: posture, problem solving and movement. The results demonstrated that interrater reliability for problem solving was not consistent. However, it was consistent for posture and movement in the client group, although less so for controls, showing increased difficulty in identifying the more subtle principles being used. Intrarater reliability was less convincing, with the therapist reporting fatigue at the number of items to be scored. However, this could be improved by reducing the number of items in the assessment because analysis showed that 39% of items did not meet the criteria for statistical significance of change. More clarification on the score measures will assist in measuring the efficacy of the treatment programme objectively. Discriminant validity of the scoring system was indicated by the improvement seen in the clients' performance but not in that of the controls. Further studies to improve reliability and demonstrate better validity are planned.