This article provides "best practice " recommendations for collecting and preserving evidence using eyewitness identification procedures. Suggested procedures are based on decades of social science research as well as the recommended practices found in the recent report on the Robert Sophonow case in Manitoba and in a 1999 U.S. National Institute of Justice document distributed to all police services in the U.S. These recommendations currently guide training programs for several police services in Canada, the U.S., and around the world, and experienced criminal investigators will recognize many of the procedures as practices they have employed in their own cases. The overarching goal of this article is to accumulate these recommendations in one place in order to allow investigators to take advantage of them and achieve a maximal level of accurate eyewitness identifications while minimizing the rate of inaccurate choices.
Criminal investigators know that it often takes many pieces of converging evidence to solve a complex case. Freshly-schooled recruits and veteran investigators alike are trained to search for, detect, collect, and preserve "obvious" physical evidence such as weapons and stolen property, as well as trace physical evidence such as fibres, hairs, fingerprints, blood, and semen. Few police officers, lawyers, scientists, or people in general, would question the importance of using the best procedures available to obtain and preserve such evidence, not to mention adherence to relevant statutory and case law. Eyewitness evidence (i.e., the testimony of victims, witnesses, and suspects, and perhaps the identification of a suspect from a live or photograph line-up), however, presents some unique problems to investigators, which in turn can lead to especially serious consequences in court.
An analysis of actual cases in the U.S. reveals that the mistaken identification of the wrong person by victims and witnesses to a crime is the single most common error leading to the arrest and conviction of innocent people (U.S. National Institute of Justice, 1996). Several cases in Canada suggest similar problems here (e.g., Regina v. McGuiness, Ballantyne & Ballantyne, 1997; Regina v. Sophonow, 1985). In addition, potentially valuable eyewitness information is sometimes overlooked by not employing optimal procedures. In either case, the result is that the actual perpetrator of the crime is still at large, either because the wrong person has been identified or because no evidence has been produced.
This article describes a set of recommendations designed to minimize the rate of eyewitness errors, while at the same time maximizing the rate of accurate identifications. The recommendations are supported by over 20 years of research, are consistent with the U.S. Guide for Law Enforcement on Eyewitness Evidence (U.S. National Institute of Justice, 1999), are the basis of training curricula for several police services in Canada and the U.S. (e.g., Ottawa-Carleton, York Region, New Jersey), and are in use by thousands of police officers in Canada and around the world (see e.g., Kebbell, 2000 for a favourable comparison between practices in the United Kingdom and these recommendations). It is hoped that the presentation of these recommendations, along with their scientific rationale, will aid in the effectiveness of investigative practices as well as the development of formalized policing procedures regarding eyewitness evidence (for similar discussions on this issue see e.g., Levi & Lindsey, 2001; Lindsey, 1999; Wells, 2001; Wells, Small, Penrod, Malpass, Fulero & Brimacombe, 1998).
A Psychological Assessment of the Eyewitness Evidence Predicament
It is certainly not a groundbreaking statement to say that memory is not perfect. Anyone who has forgotten a name, misplaced their car keys, or scored less than 100% on an exam knows that not everything people initially perceive can be recalled accurately at a later date. …