Traditional assessments of the impact and cost-effectiveness of various contraceptive methods, using couple-years of protection (CYPs) per dollar spent, do not accurately measure the level of protection offered by each method. An alternative measure--adjusted CYPs--that takes into account the relative risk of pregnancy among the users of each method is proposed here. Calculations show how cost recovery and reinvestment of the proceeds from family planning programs lead to the cross-subsidization of methods. In general, the more subsidized contraceptive methods are supported by the less subsidized methods. An examination of data from Colombia's Profamilia family planning program indicates that because of the differences in the relative risk of pregnancy of women of different ages, sterilization, the most effective contraceptive method, is not necessarily the most cost-effective method in terms of the number of CYPs it provides per unit cost.