Measuring Interjudge Sentencing Disparity: Before and After the Federal Sentencing Guidelines
用零膨胀负二项模型测量联邦量刑指南对法官间量刑差异的影响，发现指南实施后法官间平均刑期差异从17%（4.9个月）降至11%（3.9个月），适合关注量刑改革效果的学者。
This paper evaluates the impact of the Federal Sentencing Guidelines on interjudge sentencing disparity, which is defined as the differences in average nominal prison sentence lengths for comparable caseloads assigned to different judges. This disparity is measured as the dispersion of a random effect in a zero‐inflated negative binomial model. The results show that the expected difference between two typical judges in the average sentence length was about 17 percent (or 4.9 months) in 1986–87 prior to the Guidelines and fell to about 11 percent (or 3.9 months) in 1988–93 during the early years of the Guidelines. We have not sought to measure the effect of parole in the pre‐Guidelines period, other sources of disparity such as prosecutorial discretion, or the proportionality of punishment under the Guidelines as compared with the pre‐Guidelines era.