The Effects of Time in Prison and Time on Parole on Recidivism
利用美国监狱释放数据，通过工具变量分析发现，监禁时间每增加一个月，假释期间再犯概率降低1.12个百分点，但对总体再犯无显著影响；假释时间对再犯无显著作用。
In the United States, every year roughly 600,000 people are released from prison, two-thirds of them without having served their full sentence behind bars. Yet little is known about how release before full completion of sentence affects recidivism. I exploit the distinction between sentence and time served in prison to better understand how custodial and noncustodial sanctions affect recidivism. In particular, I study the effects of time in prison and time on parole on recidivism. Relying on two instrumental variables that provide independent variation in sentence and time served in prison, I do not find evidence that parole time affects recidivism. However, I find that a month in prison results in a 1.12-percentage-point decrease in the probability that an individual will reoffend while on parole, but it appears to have no effect on overall reoffending.