Inconsistent reports of sexual intercourse among South African high school students

HIV/AIDS is a pressing public health concern for youth in South Africa. Delaying sexual onset, via policy and programmatic intervention, may help to reduce prevalence rates. However, effective intervention requires accurate data on adolescent sexual behavior. Given the private nature of sexual behavior, scientists must rely heavily on self-reports. Unfortunately, these reports are not necessarily reliable; in longitudinal studies of one year or more, 4 to 12% of U.S. adolescents eventually rescind initial reports of having ever engaged in sexual intercourse. The present study aims to describe patterns of inconsistent reports of sexual intercourse among South African adolescents. Participants were 2,414 high school students from Mitchell's Plain, a low-income township near Cape Town. They responded to five semi-annual surveys on topics including sexual behavior and substance use. Of the sexually active students (n = 713), nearly 40% reported being a virgin after sexual activity had been reported at an earlier assessment. Earlier reports of sex were most likely to be retracted; 46% of youth who reported sexual intercourse at Wave 1 later rescinded, as compared to 17% of youth who reporting being sexually active at Wave 4. Inconsistent reporting could not be predicted by demographic factors, including gender, race and religion, nor could it be predicted by indices of general reliability problems (inconsistent reporting of gender and birth year). However, those with inconsistent reports of sexual intercourse were more likely to be inconsistent reporters of substance use. Implications of these results for evaluation research will be discussed.