Peer Effects and Multiple Equilibria in the Risky Behavior of Friends
利用Add Health面板数据，研究好友对在性行为等风险行为上的同伴效应，发现若朋友开始性行为，本人一年内开始的可能性增加近5个百分点，类似效应也存在于吸烟、大麻使用和逃学中。
Abstract We study social interactions in the initiation of sex and other risky behaviors by best friend pairs in the Add Health panel. Focusing on friends with minimal experience at the baseline interview, we estimate bivariate ordered-choice models that include both peer effects and unobserved heterogeneity. We find significant peer effects in sexual initiation: the likelihood of initiating intercourse within a year increases by almost 5 percentage points (on an 11% base rate) if one's friend also initiates intercourse. Similar effects are present for smoking, marijuana use, and truancy. We find larger effects for females and important asymmetries in nonreciprocated friendships.