The data for this study come from claims and enrollment files from two large employers for years 1994 and 1995. To remind the reader, Employer A is a private sector employer with over 30 locations across the United States, where each location offers the same indemnity plan and a POS managed care plan. Employer B is a large state government employer which offers an indemnity plan, a preferred provider organization (PPO) plan, and seven health maintenance organization (HMO) plans. A description of the features and costs of each plan is given in Chapter 2.
For this risk-adjustment study, the sample from Employer A was limited to employees age 18 to 65; data on dependents were not available. The POS plan was not offered in 1994, so the data for Employer A come from the indemnity plan only. The total sample included 68,904 employees. The sample used to estimate the models for Employer B consisted of 171,644 employees, dependents, and retirees under age 65.