Estimating the Deterrent Effect of Incarceration Using Sentencing Enhancements
研究利用各州枪支附加法通过时间的差异，分离出监禁的威慑效应，发现该法实施三年内使持枪抢劫下降约5%，且对其他犯罪无显著溢出。
Increasing criminal sanctions may reduce crime through two primary mechanisms: deterrence and incapacitation. Disentangling their effects is crucial for optimal policy setting. I use sentence enhancements due to the introduction of state add-on gun laws to isolate the deterrent effect of incarceration. Using cross-state variation in the timing of law passage dates, I find that the average add-on gun law results in a roughly 5 percent decline in gun robberies within the first 3 years. This result is robust to a number of specification tests and does not appear to be associated with large spillovers to other types of crime.