Issues and biases in matching medicaid pregnancy episodes to vital records data: the Arkansas experience.

Objectives: This study examines the extent of selection biases identified in the process of linking Medicaid claims with evidence of pregnancy to vital records.

Methods: Two years of Medicaid claims were scanned to identify pregnancy-related diagnoses and procedures. Information on 55,764 Medicaid recipients was provided to the Division of Health Statistics, which linked the information to vital records data on a range of identifying characteristics.