摘要：We introduce the best-friend methodology for using surveys to measure the population prevalence of sensitive behaviors. We demonstrate the effectiveness of this tool by comparing self-reports to best-friend reports of sexual behavior and abortion history among young women in Malawi (n = 1493). Best-friend reports reveal higher and more believable estimates of abortion and multiple sexual partners. In contexts in which best friends commonly discuss such behaviors, best-friend reports are an inexpensive and easily implemented tool. Survey researchers struggle to measure sensitive and stigmatizing behaviors that are critical for understanding health risks, patterns of disease transmission, and contraceptive need. 1 – 4 Novel methodological approaches to reduce underreporting, including audio computer-assisted self-interviewing and confidential voting techniques, have had limited success. These methods can elicit higher (and arguably more accurate 5 ) reports of certain sexual behaviors and abortion, but they produce lower reports of other behaviors and can increase reporting errors. 6 – 11 To better estimate the population prevalence of sexual risk behavior and abortion in a community in southern Malawi, we administered a survey asking a series of questions about the behaviors of the respondent's best friend. This method leverages 2 sociological insights. The first is that friendship networks are homogenous; friends tend to be similar with respect to sociodemographic characteristics and behaviors. 12 The second is that social desirability bias should have less influence on reports of the sensitive or stigmatizing behaviors of one's friends than on self-reports. 13 Here we present the initial results obtained by using this easily implemented approach to survey research on sensitive topics. Malawi is in the midst of a generalized and mature AIDS epidemic. Young women are particularly likely to become infected, with HIV incidence peaking in the mid-20s. 14 Premarital sex, although common, is nonnormative, creating a social desirability bias that encourages individuals, and women in particular, to underreport extramarital partnerships and sexual activity before marriage. 15 , 16 Abortion is illegal in Malawi except to save the life of the pregnant woman. 17 , 18 Nonetheless, clandestine abortion—largely unsafe—is a common response to unwanted or mistimed pregnancies throughout the country. There are no nationwide estimates of abortion in Malawi, but data from major hospitals suggest that abortion complications are the most common reason for hospital admission to gynecological wards. 19 , 20
