Internal validation of Medicaid Analytic eXtract (MAX) data capture for comprehensive managed care plan enrollees...

Because of concerns over incomplete medical encounter capture in Medicaid capitated comprehensive managed care (CMC) plans, researchers have traditionally confined analyses to fee-for-service (FFS) enrollees. We aimed to evaluate the usability of data for CMC enrollees in Medicaid Analytic eXtract (MAX) files for 29 states from 2007 to 2010.

We applied 7 measures to MAX inpatient, other therapy, and prescription drug files for each state and study year. Four measures were based on "connectivity" criteria where we expected use of a select essential service to be closely connected to another, resulting in "service pairs." Three measures were based on "continuity" criteria where we expected patients to continue chronically used services or treatments when they switched enrollment from FFS to CMC plans. High proportions of continuity and comparable proportions of patients with complete service pairs relative to FFS enrollees may suggest complete data capture for CMC enrollees. Data of states that met preset criteria were considered usable for research and policy analyses.

The completeness of CMC enrollees' data in MAX varied by states. Among 22 states having at least 5% CMC plan enrollment, data of 12 states met our quality standard and were considered usable starting in 2007. Four states had usable data starting in 2008 and one in 2009.

The completeness of CMC enrollees' data in MAX improved over the study period. In 17 out of 29 states, CMC enrollees' data in selected years were comparable with FFS enrollees and can be considered for use in analysis.