How You Rate Depends on Who Investigates: Partisan Bias in ABA Ratings of US Courts of Appeals Nominees, 1958–2020

Recent work on the federal judicial nominations process finds relationships between nominees’ characteristics, such as partisanship and gender, and American Bar Association (ABA) ratings. While the findings inform public debate about ABA involvement in the nomination, the studies do not take into account the characteristics of the individuals who investigate the nominees. This study adds investigator partisanship to understand more completely the relationship between nominees and their ABA ratings. The results indicate that the Standing Committee on the Federal Judiciary (SCFJ) investigators’ partisanship contribute systematically to a nominee’s likelihood of receiving a higher or lower ABA rating. The probability that a Republican nominee receives the highest rating does not vary with the investigator’s partisanship. Democratic nominees, however, have the highest chance of the top rating after an SCFJ investigation led by a co-partisan. An analysis of matched data from the whole dataset reproduces the basic pattern of results, while the implementation of matching to partisan subgroups of nominees uncovers that both parties may benefit roughly equally from investigations led by co-partisans.