Changes in health plans serving Medicaid, 1993-1996.

To better understand the Medicaid managed care market during a period of rapid change, we developed a new data set that links Medicaid enrollment data with health maintenance organization (HMO) industry data for 1993-1996 to analyze Medicaid enrollment in full-risk health plans. Nearly half of the Medicaid enrollees in a fully capitated managed care arrangement were in plans in which Medicaid makes up at least 75 percent of the total enrollment. In addition, the number of Medicaid-only plans has more than doubled since 1993. Commercial-based plans participated increasingly in Medicaid managed care during the period, yet more than half of the plans entering the Medicaid market were newly formed.