Do Surveillance Cameras Affect Unruly Behavior? A Close Look at Grandstands
利用瑞典足球联赛中不同体育场引入监控摄像头的时间差异作为自然实验，发现摄像头使不守规矩行为减少约65%，为监控政策效果提供了因果证据。
Abstract How do surveillance cameras affect unruly spectator behavior? I examine this question using a natural experiment from the Swedish soccer league. Stadiums in Sweden introduced surveillance cameras at different points in time during the years 2000 and 2001. I exploit the exogenous variation that occurred because of differences across stadiums in the processing time taken to obtain permits for cameras as well as delays in the supply of equipment. Conditioning on stadium fixed effects, unruly behavior was found to be approximately 65 percent lower in stadiums with cameras compared to stadiums without cameras. The identification strategy provides a unique possibility to address problems regarding endogeneity, simultaneous policy interventions, and displacement effects.