Various procedures for estimating the effectiveness of a method of contraception have been devised. These measures, in turn, have been used in populations which differ widely in their propensity to use contraceptives properly. Therefore, a wide array of failure rates is available in the family planning literature. Unfortunately, because of differences in measurement and in choice of population, a random selection of these reported failure rates will not produce a consistent ordinal or cardinal ranking of methods by their effectiveness. Moreover, such a wide variety or reported rates permits the family planning practitioner to choose selectively in order to maximize the attractiveness of his favorite method(s). By surveying family planning personnel in two major cities, we found that they do indeen appear to place the methods they actively dispense in an extremely favorable position. Specifically, they are biased against the traditional contraceptives, foam and the condom. In this paper, we discuss the theoretical underpinnings of the measurement of effectiveness, report the apparent bias in the levels of contraceptive effectiveness reported to the patient, and finally, recommend a procedure for eliminating the jumble of rates in the literature and the consequent confusion among family planning personnel.