Reexamining Criminal Behavior: The Importance of Omitted Variable Bias
发现逮捕率与定罪率、服刑时间负相关，遗漏这些变量会使逮捕率对犯罪率的影响被低估多达50%，且定罪率对犯罪率有显著解释力。
Recently many papers have used the arrest rate to measure punishments in crime-rate regressions. However, arrest rates account for only a portion of the criminal sanction. Conviction rates and time served are theoretically important, but rarely used, and excluding them generates omitted variable bias if they are correlated with the arrest rate. This paper uses the most complete set of conviction and sentencing data to show that arrest rates are negatively correlated with these normally excluded variables. Consequently, previous estimates of arrest-rate effects are understated by as much as 50%. Also, conviction rates, but not sentence lengths, have significant explanatory power in standard crime-rate regressions. © 2003 President and Fellows of Harvard College and the Massachusetts Institute of Technology.