Do Teenagers Respond to HIV Risk Information? Evidence from a Field Experiment in Kenya

We use a randomized experiment to test whether and what information changes teenagers' sexual behavior in Kenya. Providing information on the relative risk of HIV infection by partner's age led to a 28 percent decrease in teen pregnancy, an objective proxy for the incidence of unprotected sex. Self-reported sexual behavior data suggests substitution away from older (riskier) partners and toward same-age partners. In contrast, the official abstinence-only HIV curriculum had no impact on teen pregnancy. These results suggest that teenagers are responsive to risk information, but their sexual behavior is more elastic on the intensive than on the extensive margin.

本研究通过随机试验，检验肯尼亚青少年的性行为是否会因信息传递而发生改变，以及哪些类型的信息可对其性行为产生影响。向青少年传递按伴侣年龄划分的HIV（人类免疫缺陷病毒）感染相对风险信息后，青少年妊娠率下降了28%——而青少年妊娠是无保护性行为发生率的客观替代指标。自我报告的性行为数据显示，青少年会规避年龄较大（感染风险更高）的伴侣，转而选择同龄伴侣。与之形成鲜明对比的是，官方推行的仅倡导禁欲的艾滋病预防课程对青少年妊娠率无显著影响。上述结果表明，青少年对风险信息具有响应性，但其性行为的集约边际弹性高于外延边际弹性。