Empirically based conversion factors for calculating couple-years of protection

Couple-years of protection (CYP) is one of several commonly used indicators to assess international family planning efforts. It has been the subject o f much debate, relating in part to the specific conversion factors used to translate the quantity of the respective contraceptive methods distributed to a single measure of protection. This article outlines a comprehensive ef fort to revisit those conversion factors based on the best available empiri cal evidence. In most instances, the analysis supports previously establish ed standard conversion factors. However there are two notable departures. F ewer condoms and spermicides are recommended for each CYP (120 vs. 150), pr imarily because coital frequency among condom users is lower than previousl y assumed. Furthermore, for sterilization, the authors recommend the use of country or region-specific conversion factors. Every program evaluation in dicator has strengths and weaknesses, and the best program evaluation effor ts use a variety of indicators. If CYP is used to evaluate programs, howeve r the authors believe that the conversion factors presented reflect the bes t available evidence.