The nation's most trusted consumer's advocacy group, the Consumer's Union (CU), interviewed 3,300 of its readers in order to determine the effectiveness of condoms at preventing conception and disease. CU also mechanically tested 16,000 condoms of 37 different varieties and brands. The results of its studies, as reported in the March 1989 issue of Consumer Reports, are revealing indeed.
About one-fourth of the Consumer Union's readers reported at least one instance of condom breakage in a one-year period, and about one in eight experienced two or more incidents of breakage in one year.[2]
Using these and other data, CU estimated that an average of one condom in 165 broke during heterosexual intercourse, and about one in 105 broke during anal intercourse. This failure rate was much lower than that produced by most other studies.
Resulting Pregnancies. The resulting 0.6 percent (1/165) condom breakage rate for normal heterosexual intercourse, when extrapolated over an average of 100 acts of intercourse each year, and accounting for the woman's periods of infertility, results in a method effectiveness rate of about 95.5 percent per year.[3]
"Method effectiveness" is the best rate that can possibly be expected, since it accounts only for failures in the condom but not for failures in use.
"Contraceptive failure" is defined as the percentage of women who become pregnant while using one method of contraceptive exclusively for one year. This category includes both failure of the method (such as physical condom breakage as found by CU), and failure of the user to employ the method properly.
If we include mistakes in condom usage, the actual effectiveness rate of the prophylactic is 89.2 percent per year.
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