Reliability of Medicaid claims files for use in psychiatric diagnoses and service delivery.

To investigate the reliability of Medicaid claims data for use in research, clinical decision-making, and policy, medical records were abstracted of 105 inpatient stays on the psychiatric service of a large general hospital. Primary and secondary diagnoses and outpatient specialty mental health services after hospitalization were compared between Medicaid claims data and medical record information. Primary and secondary diagnoses were reliable, but claims data failed to capture several types of outpatient services. This suggests strategies to use claims files more appropriately.