Evaluation of contraceptive history data in the Republic of Korea.

The consistency of retrospective and current status data on contraceptive use from a series of national fertility surveys carried out during the 1970s in Korea is investigated. Aggregate consistency is examined among random samples from the same cohort or cohorts of women interviewed in each survey. The results indicate that estimates of trends in contraceptive use from a retrospective history in one survey, or from cross-sectional estimates in a series of surveys, can each yield misleading findings. Data from the 1974 Korean National Fertility Survey (KNFS) appear to be more reliable than those from other surveys, possibly because an interval-by-interval contraceptive history was used, explicit definitions of contraceptive methods were given prior to taking the contraceptive history, and the KNFS involved longer interviewer training and, perhaps, less time pressure during interviews.