Combining state administrative databases and provider records to assess the quality of care for children enrolled in Medicaid.

Our objective was to assess the capability of state administrative health care databases to evaluate the quality of immunization rates for a Medicaid managed care population. Data on 5599 2 year olds were obtained from a Medicaid claims database, a health department database, and the records of the children's assigned providers. The study was conducted on 1 managed care program in 1 state. Test performance ratio analyses were used to assess the relative accuracy and contribution of each source of administrative data. We found that of the 67,188 doses needed, 45,511 (68%) were documented as administered per at least 1 of the data sources. Medicaid claims data alone accounted for 18% of immunized children, while health department data used by itself accounted for 12%. Together, these 2 sources identified 34% of immunized children. Large administrative databases, such as Medicaid claims and data from a health department, while valuable sources of information on quality, may underestimate outcomes such as immunization rates. Assessments of the quality of health care should rely on a combination of administrative data and providers' records as sources of information.