ABSTRACT
The Computerized On-line Medicaid Pharmaceutical Analysis and Surveillance System (COMPASS) is a data base composed of Medicaid billing data. COMPASS derives its data as a by-product of the Medicaid Management Information System, which is a computerized claims processing and management information program for this large health care system. The principal advantage of COMPASS is the very large population available for study. There are currently 8.9 million patients from 10 states in the data base. To illustrate the large sample size available for study, researchers identified 88,000 patients during 1980 from two states who were exclusively dispensed one of seven nonsteroidal antiinflammatory drugs. There are several significant disadvantages that should be considered when using this data base. Information is not available on inpatient drugs or over-the-counter drugs. There is a time lag before data is entered into the system which may delay the study of newly marketed drugs.
