Peer Effects in Product Adoption
利用Facebook去识别数据，通过随机手机丢失导致的同伴新购手机变化，发现朋友购买同品牌手机显著且持久地提升个人需求，但可能降低对竞争品牌的需求。
We use de-identified data from Facebook to study the nature of peer effects in the market for cell phones. To identify peer effects, we exploit variation in friends' new phone acquisitions resulting from random phone losses. A new phone purchase by a friend has a large and persistent effect on an individual's own demand for phones of the same brand. While peer effects increase the overall demand for phones, a friend's purchase of a particular phone brand can reduce an individual's own demand for phones from competing brands, in particular if they are running on a different operating system.