How do Medicaid managed care program managers use enrollment and disenrollment information to manage their programs? What does a low disenrollment rate imply about health plan (and enrollment broker) performance? Are people who select a health plan less likely to disenroll than those who are assigned to a plan? What elements of an enrollment system lead to a higher level of voluntary selection and / or lower level of disenrollment? This paper seeks to answer these questions, among others.