Linking birth certificates with Medicaid data to enhance population health assessment: methodological issues addressed.

This study linked birth certificates with Minnesota Medicaid deliveries in order to identify Medicaid births. This article describes the link between methodology and results. Medicaid claims from 1997 were used to identify women with a delivery code. Identifiers for these women were linked to birth certificate files, with a match rate of 93.2 percent. Women's match status did not differ by maternal age. Women in some border counties matched at much lower rates than the rest of the population. The methodology was effective in linking Medicaid and birth certificate data and will be implemented as a data linkage protocol for Minnesota.