How well will HEDIS 3.0 address the Medicaid population?

State Medicaid agencies have been looking for a standardized method to address the performance of managed care plans with which they contract. Although the recent release of the Health Plan Employer Data and Information Set for Medicaid plans was intended to satisfy this need, in the current and rapid evolution of performance measurement, it may be too little and too late. The author, one of the members of the original Medicaid HEDIS work group, describes some of the core challenges HEDIS 3.0 will face in improving on the Medicaid data set.