Provocative new empirical paper claims to identify the "most discriminatory" federal sentencing judges

Via Twitter, I was altered to this notable new empirical paper by multiple authors titled "The Most Discriminatory Federal Judges Give Black and Hispanic Defendants At Least Double the Sentences of White Defendants."  The paper's title alone likely explains why I describe it as provocative, and this abstract provides more context about the paper's contents:

In the aggregate, racial inequality in criminal sentencing is an empirically well- established social problem. Yet, data limitations have made it impossible for researchers to systematically determine and name the most racially discriminatory federal judges.  The authors use a new, large-scale database to determine and name the observed federal judges who impose the harshest sentence length penalties on Black and Hispanic defendants.  Following the focal concerns framework, the authors (1) replicate previous findings that conditional racial disparities in sentence lengths are large in the aggregate, (2) show that judges vary considerably in their estimated degrees of racial discrimination, and (3) list the federal judges who exhibit the clearest evidence of racial discrimination.  This list shows that several judges give Black and Hispanic defendants double the sentences they give observationally equivalent white defendants.  Accordingly, the results suggest that holding the very most discriminatory judges accountable would yield meaningful improvements in racial equality.

The "new, large-scale database" used for this study is this JUSTFAIR data source published online last year.  I have not previously blogged about the JUSTFAIR data because I have never been sure of its representativeness since the source says it includes nearly 600,000 cases over a recent 18-year period (from 2001 to 2018), but more than twice that number of persons have been sentenced in federal courts during that span.  I fear I lack the empirical chops to know just whether to be reasonably confident or highly uncertain about the JUSTFAIR data, and that broader concern colors my thinking about this provocative new paper's claims that the authors have been able to identify the "most racially discriminatory federal judges."

I would love to hear from readers with strong empirical backgrounds about whether this new paper effectively demonstrates what it claims to identify.  I am initially skeptical because the the two judges labelled "most discriminatory" come from the same federal judicial district and only a few districts are among those that have all the identified "discriminatory" judges.  That reality leads me to wonder if case-selection realities, rather than "discrimination," may at least in part account for any observed racial differences in sentencing outcomes.  Relatedly, when I dig into the local data at the JUSTFAIR data site, the judges identified in this new paper as the "most discriminatory" do not seem to have anywhere close to the most racially disparate rates of above/below guideline sentencing outcomes even within their own districts.

In short, without a much better understanding of the empirics at work here, I am not confident about what this new empirical paper is claiming.  But I am confident that I would like to hear from readers as to what they think about this provocative new paper on an always important topic.