COLLABORATIVE RESEARCH: Why do forensic evaluators with access to the same information come to different conclusions when retained by opposing sides in legal proceedings?

Sam Houston State University, Huntsville TX

Investigators

Abstract

How objective are expert witnesses when they are retained by one side in adversarial legal proceedings? The social sciences have offered almost no data to address "adversarial allegiance," the presumed tendency for experts to reach conclusions that support the party who retained them. Recently, the principal investigators found strong evidence of adversarial allegiance among some forensic evaluators who scored risk assessment instruments for sex offenders facing trial. But only carefully-controlled experimental research can identify why adversarial allegiance exists. This study uses an experimental design to examine a) whether allegiance effects in risk assessment scores occur when evaluators in adversarial proceedings do not get to choose the side of the case they work for, and b) the extent to which evaluators' conclusions appear to be the product of decision making processes that are known to lead to biased conclusions in other contexts. Participants are forensic evaluators and graduate students who score offender risk measures for one side in a sex offender trial. Participants will complete questionnaires before and after they score offender data, allowing researchers to assess the pre-existing attitudes and the decision making processes associated with any allegiance effect. Results will help courts better scrutinize expert scientific testimony. Results will also inform training curricula to reduce bias in forensic psychological evaluation, and perhaps in other forensic science disciplines. Regardless of their discipline, experts who are retained by one party in adversarial legal proceedings are probably vulnerable to allegiance for similar reasons. Eventually, a research program that identifies the processes underlying adversarial allegiance can inform interventions to minimize these processes.