Can We Believe What We See, If We See What We Believe? -- Expert Disagreement

• NCJ Number: 138349
• Journal: Journal of Forensic Sciences Volume: 37 Issue: 4 Dated: (July 1992) Pages: 1115-1124
• Author(s): J J Nordby
• Date Published: 1992
• Length: 10 pages
• Publication Format: Article
• Publication Type: Survey
• Language: English
• Country: United States of America
• Note: Paper presented to the American Society of Forensic Odontology, American Academy of Forensic Sciences meeting, 1991, Anaheim, California

Annotation

Forensic experts often disagree, and possible sources of such disagreement are analyzed.

Abstract

The logic of interpreting crime scenes and pattern injuries is explained to locate potential sources of interpretive error and to recommend strategies that will minimize errors in case preparation. Cases show that both practical and theoretical investigative expectations affect forensic observations and that these expectations confer evidential status on the artifact. When two observers' expectations conflict, they do not see the same thing and are therefore not presented with the same evidence. When inappropriate, expectations cause observational errors of a unique sort, supplying one source for disagreement. When inferences are made from inappropriately sanctioned observations, interpretive errors are compounded, and the resolution of disagreement becomes difficult. The forensic expert's role is to refine the context of observation, based on expert understanding. To refine the context of observation, the expert must assess the entire crime scene, noting competing explanations, and must refuse to be guided by inappropriate or preconceived expectations.