Stephanie Holmes Didwania (Temple University – James E. Beasley School of Law) has posted (How Much) Do Mandatory Minimums Matter? on SSRN. Here is the abstract:

Understanding the relationship between mandatory minimums and sentencing outcomes is often difficult due to the endogeneity of mandatory minimum charging. This paper examines the prosecutorial and judicial response to what was arguably the most sweeping change to mandatory minimum charging policy in the last several decades: an August 2013 memo promulgated by then-Attorney General Eric Holder instructing all federal prosecutors to stop charging mandatory minimums in drug cases involving certain low-level offenders. This paper shows that the charging policy did not work as intended. Although prosecutors appear to have complied with the Memo’s charging directive, the policy change at most modestly reduced sentences for eligible defendants. I suggest that the Memo’s failure to meaningfully reduce sentence length in the eligible population can be explained by two facts. First, prior to the policy change, many defendants who would have been eligible to benefit from the Memo already received sentences below the mandatory minimum through two statutory exceptions. Second, the U.S. Sentencing Guidelines, which are tied to the mandatory minimum provisions, were not affected by the Memo.
One might also expect that the Memo would have reduced racial disparity in sentencing in light of prior work showing that black defendants are more likely to be charged with mandatory minimums than similarly-situated white defendants, and that this charging disparity contributes to sentencing disparity. I do not find evidence that the Memo affected sentencing disparity. I conclude that advocates seeking to reduce sentences for federal drug defendants should expand their efforts to promoting interventions that reach more serious offenders and on reforming the U.S. Sentencing Guidelines.