This paper focuses on assessment of asthma-management outcomes resulting from interventions for patients. Noted is the need to design both programs and evaluations that reflect a theoretical understanding of behavior change. For purposes of illustration, the theoretical construct of self-regulation is used. It is posited that individuals are predisposed to take action to handle asthma problems by virtue of internal (knowledge, attitudes, beliefs) and external (models of behavior, technical advice and service, money, etc.) factors. Through processes of self-regulation—that is, the ability to observe, make judgments, and react to one's own behavior—individuals learn which management strategies (prevention, symptom management, negotiation, and communication) work for them. If these management strategies are effective, one would expect certain outcomes: the patient's personal goal will be reached; physiologic and psychological health status will be maintained or improved; and health care use will be appropriate. A range of good studies of patient behavior related to asthma management and of interventions to enhance behavior are available, and provide some evidence that these outcomes can be attained. A solid foundation for the development of more sophisticated and refined self-management assessment measures is available. Objective measures have been used to verify behavior in two or three research projects. Although objective measures are costly and can be cumbersome to administer, more effort to develop and use such measures is needed. Testing of the reliability and validity of existing patient-management measures has been perfunctory, and greater attention, especially to the validity of measures, is needed. Six recommendations for better measurement are made.