"As reflected in these figures, the difference between the average guideline minimum and the average sentence imposed has generally widened since the Booker and Gall Periods, suggesting an overall decline in the influence of the guidelines over time. Although the difference continued to widen in the Post-Report Period, it appears to have stabilized after peaking in 2014. In fact, the analysis of the years that followed from 2015 through 2017 demonstrated a small gradual decrease in the difference between the average guideline minimum and average sentence imposed in those years.
"This trend is first demonstrated in the two-line graph, which shows a gradual widening of the spread between the average guideline minimum and average sentence imposed. In the Booker Period, the average sentence imposed was 8.7 months lower than the average guideline minimum. In the Gall Period, the average sentence imposed was 9.9 months lower. And in the Post-Report Period, the average sentence imposed was 13.2 months lower. However, in the most recent years of the Post-Report Period, average sentences imposed generally paralleled average guideline minimums—that is, where the average guideline minimum increased or decreased, so did the average sentence imposed — which suggests a stabilization in the influence of the guidelines."
The Influence of the Guidelines on Federal Sentencing: Federal Sentencing Outcomes, 2005-2017. US Sentencing Commission, Dec. 14, 2020.