A comprehensive state-of-the-art system for quality improvement in ambulatory care has been designed to test (1) whether patients at 8 intervention sites demonstrate improved health status and satisfaction with their care as compared to patients at 8 control sites and (2) the extent to which timely patient self-reported data influences provider practice patterns. During the study pilot period, several investigators developed, tested and analyzed disease-specific questionnaires for 7 common chronic conditions. An advanced automated information system was designed to link hospital computer information and patient questionnaire data in order to provide timely communication between patients and providers about important health problems. This report briefly describes the 3-year quality of ambulatory care clinical trial and details the development and pilot testing of the disease specific questionnaire for diabetes. Reliability testing showed correlations were higher for fixed events such as foot ulcers than for subjective judgments such as satisfaction with providers. Responsiveness testing indicated that this questionnaire could measure behavior and care modifications in patients 6 months following an outpatient education course, compared to the baseline pre-education values. Diabetes severity information has been collected from self-administered questionnaires and laboratory data to assist providers in assessing the patients' likelihood of 4-year mortality. It is anticipated that the rapid identification of important patient issues will assist patients and clinicians in mutually addressing and resolving health care problems, thereby improving the quality of outpatient care.