First Advisor

Christopher Shortell

Date of Publication

Spring 5-22-2018

Document Type


Degree Name

Doctor of Philosophy (Ph.D.) in Public Affairs and Policy


Public Affairs and Policy




Judicial process, Administration of justice -- Decision making, Expert evidence



Physical Description

1 online resource (ix, 297 pages)


Over the last several decades, multiple schools of thought have emerged regarding what impacts judicial decision making. In contrast to the classic legal model, studies have argued alternatively that judges are policy actors who rule consistent with their political attitudes; that behavioral traits such as race, gender and socialization influence judicial conduct, both consciously and unconsciously; that whatever policy interests judges may have, these are moderated by institutional constraints and strategic considerations; and that judges are subject to some common cognitive shortcuts in decision making, although they may be moderated or present differently than in the general population in light of their training and experience.

Most of these studies, particularly in political science, have tended to focus on Supreme Court or appellate decisions on politically salient subject matter such as the scope of the Fourth Amendment or racial discrimination. The cognitive studies, by comparison, have primarily used experimental conduct, often with artificially extreme variations between legal and factual issues to assess the impact of legal training. Other than field review articles, most have focused on a single potential explanatory variable such as ideology, gender or legal training. To date, there has been very limited study of the more routine tasks judges engage in at the trial court level such as pre-trial evidentiary rulings or comparative assessments of the relative explanatory power of factors drawn from multiple approaches to decision making.

The present study involved both a qualitative and quantitative assessment of Federal district court decisions on the admissibility of expert witnesses. Employing thematic analysis of all cases involving a substantive analysis of this issue from 2010-2015 in nine district courts, a default pattern emerged that judges are reluctant to exclude experts except in extreme cases. Moreover, judges appear to have adopted several practices consistent with minimizing the cognitive burden of decision making. These findings suggest that judges are acting consistently with legal norms and the broad outlines of legal precedent, but in a manner which may lead to sub-optimal outcomes in some circumstances. Quantitative analysis of the same data suggests that judges are subject to a variety of significant influences including legal precepts, political ideology and cognitive heuristics in different settings. Moreover, the influence of issues such as ideology appear to be associated with some courts and not others, with circuit level precedent being the most obvious intervening factor to explain the difference.

The circuit level impacts on behavior and several other findings in this study suggest that much more nuance is present than is normally acknowledged in the study of judicial decision making. The results of this study also suggest policy makers should account for cognitive tendencies in crafting legal standards and precedents as well as legal education. Finally, it posits that practitioners can maximize their odds of success on motions to exclude expert witnesses through similar awareness of what influences judicial conduct, especially but not limited to cognitive limitations in rendering judgments under time constraints and conditions of uncertainty.


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