Science, Technology, or the Examiner Experience: What Influences Jurors' Judgments About Forensic Science Testimony?

47 Pages Posted: 13 Nov 2017 Last revised: 28 Nov 2017

See all articles by Jonathan J. Koehler

Jonathan J. Koehler

Northwestern University - Pritzker School of Law

N. J. Schweitzer

Arizona State University

Michael J. Saks

Arizona State University (ASU) - Sandra Day O'Connor College of Law

Dawn E. McQuiston

Wofford College

Date Written: November 9, 2016

Abstract

The impact of forensic science evidence on jurors’ judgments is critically important to the criminal justice system. The assignment of low or high weight to such testimony can be the difference between acquittal or conviction. Many of the traditional forensic sciences (e.g., fingerprints and bitemarks) draw their strength largely from the subjective judgments of examiners who testify about whether evidentiary prints or other markings are consistent with (or “match”) known markings from a person or object. In an online experiment (Experiment 1) and a realistic jury simulation using actual jurors or jury-eligible adults (Experiment 2), this paper investigates three factors that might affect how jurors think about and use forensic science evidence. These factors are (a) whether the forensic science method had been scientifically tested, (b) the forensic scientist’s background and experience, and (c) how sophisticated the forensic science technology is. The results show a strong and consistent effect for examiner background and experience on evidence strength judgments, no effect for forensic technology sophistication, and a limited and inconsistent effect for scientific testing (present in the online experiments, absent in the realistic jury simulation). These findings raise concerns about potential undue influence of examiner background and experience on jurors’ judgments, and lack of clear influence of scientific testing. The implications of our findings for criminal justice practices and policies are considered.

Suggested Citation

Koehler, Jonathan J. and Schweitzer, Nicholas J. and Saks, Michael J. and McQuiston, Dawn, Science, Technology, or the Examiner Experience: What Influences Jurors' Judgments About Forensic Science Testimony? (November 9, 2016). Northwestern Law & Econ Research Paper No. 17-19. Available at SSRN: https://ssrn.com/abstract=3068471 or http://dx.doi.org/10.2139/ssrn.3068471

Jonathan J. Koehler (Contact Author)

Northwestern University - Pritzker School of Law ( email )

375 E. Chicago Ave
Chicago, IL 60611
United States

Nicholas J. Schweitzer

Arizona State University ( email )

PO BOX 37100
Phoenix, AZ 85069-7100
United States

HOME PAGE: http://lsprg.asu.edu

Michael J. Saks

Arizona State University (ASU) - Sandra Day O'Connor College of Law ( email )

Box 877906
Tempe, AZ 85287-7906
United States

Dawn McQuiston

Wofford College ( email )

United States

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