This has been a brief review of the HOAC system. Direct access and the use of other algorithms to guide this process fit well with the HOAC system. An example would be an algorithm designed to guide the physical therapist through the process of being the first evaluator of a patient with low back pain (Physical Therapy Department, US Public Health Service Hospital, San Francisco, Calif; unpublished data; 1976). The review of the system occurs at the first step (collect initial data). The examination of the patient occurs at step three. Step four would be to generate a working hypothesis that could lead either to referral to an appropriate practitioner or to continuation through the next step in this algorithm. The HOAC system requires the physical therapist to deal with defined problems and to document the actions that have been taken. This system lends itself to peer review and quality assurance questions. It helps the physical therapist to review his or her own performance, and it can help to identify weaknesses in patient management and at which step in the process these weaknesses occurred (eg, at the goal-setting level, at the hypothesis-generation level). By creating a better understanding of the performance of the physical therapist, this model can help determine which continuing education needs must be met. This method can also help us to understand the scientific basis for practice in that it requires testing of assumptions of treatment planning and goal achievement.(ABSTRACT TRUNCATED AT 250 WORDS)