Effect of a computerized ambulatory medical record system on the validity of claims data.

Relationships were compared between claims data and charts data in a medical practice when a paper chart and manually prepared claims forms were used and after implementation of a computerized medical record system (COSTAR) in which claims data were derived automatically from the medical database. Claims data and chart data resembled each other more closely when the computer system was used, suggesting that claims data derived in this manner may have particular value in health care planning and research.