The purpose of this extracted data file was to create an Exposure Interval File compatible with an analysis of contraceptive failure, using data from Cycle III of the National Survey of Family Growth (NSFG). NSFG data were originally collected by the National Center for Health Statistics; information on the original survey can be found in the NCHS documentation for Cycle III Public Use Sample Data Tape, or in the User's Guide for Data Set 26 prepared by the Data Archive on Adolescent Pregnancy and Pregnancy Prevention (DAAPPP).

In all, the 7,969 respondents to the NSFG contributed 11,253 separate, cotinuous intervals of exposure that met the criteria described above. Continuous intervals separated by changes in marital status and/or by periods of no intercourse were coded as multiple intervals, yielding 12,962 intervals available for analysis. For each of these 12,962 intervals, 34 interval-related characteristics are available from this data file.