The evaluation of the data collection process for a multicenter, population-based, case-control design.

This report details the methods the authors used to conduct the Cancer and Steroid Hormone Study, a multicenter, population-based, case-control study of oral contraceptive use in relation to breast, endometrial, and ovarian cancer diagnosed during 1980-1982. The authors have documented their methods and rationale, and the results of their data collection efforts as a practical guide for the planning and conduct of large case-control studies. They observed the following: 1) the Surveillance, Epidemiology, and End Results program is a useful epidemiologic resource for identifying cases from which to evaluate risk factors for cancer in the United States; 2) random digit dialing is an effective and efficient method for screening for eligible controls for a population-based study; 3) with the cooperation of community pathologists, histologic specimen slides can be retrieved and reviewed for diagnostic confirmation and histologic subclassification of cancer for greater than 95% of the cases interviewed; and 4) data reported during personal interviews of study participants can be validated by reviewing medical records for more than 75% of study participants who reported medical events that occurred during the 10 years before the beginning of the study.