Sample Selection for the Prescription Drug Information Study

The Prescription Drug Information Study was designed to determine how variations in informational leaflets (patient package inserts or PPIs) given out with prescription drugs affect patients' knowledge, attitudes, and behavior. This Note summarizes the objectives, procedures, and outcomes of sample selection for the Prescription Drug Information Study. It describes how pharmacies were selected for participation in the study and how customers were recruited from those pharmacies. It reports on the characteristics of the resulting samples of pharmacies and customers and assesses how well they meet the study's sampling goals. It also provides information about the success of procedures for randomly assigning PPIs and examines the effects on the sample of uncooperative pharmacies and pharmacy customers. The data supply important evidence concerning the validity of the study's main findings.