Identification Tests, Best Practices in

Perhaps the ultimate form of eyewitness evidence is the identification of a suspect from a live or photo lineup, as opposed to more general information provided by a witness, such as a verbal description of an event. Best-practice recommendations in this area are based on a combination of some good procedures used by law enforcement for decades, sound logic and probability theory, basic psychological principles, and dedicated psychology–law research. The primary goal of a good identification procedure is to let the witness's memory be the basis of his or her decision, rather than any implicit or explicit influences that derive from either the procedure used or the nature of the lineup itself. And, of course, the desired outcome of a good procedure is to secure either an accurate identification of a guilty suspect or a “Don't know” or “Not there” response if the actual offender is not in the lineup.

There are at least four techniques for obtaining an identification from an eyewitness, and most of the bestpractice procedural recommendations apply in all of them (as opposed to filler-selection issues, for example, which don't apply for at least one of the techniques). The two techniques that have received the most attention by researchers and the legal community, and are the primary focus of this entry, are live lineups (also known as identification parades in the United Kingdom and some other countries) and photo lineups (also known as photo arrays or photo spreads and sometimes called a “6-pack” in the United States, in reference to the most common number of photos used). The other two procedures are the field identification procedure (often called a “showup”), in which just one individual is shown to a witness, usually soon after an event has occurred and within close proximity to the scene, and the in situ procedure, in which a witness is asked to view a group of individuals in a relatively informal setting, such as the lobby area of a police station or a public location that a suspect is known to frequent, such as a bar or a place of employment.

The showup is thought by most eyewitness researchers, and some courts, to be “inherently suggestive,” and few researchers would recommend it as a best-practice technique. The two most obvious potential advantages of a showup are that a potentially dangerous person could be detained on the basis of a positive identification, often with the aim of protecting a person who might be revictimized otherwise, and that an innocent suspect could be quickly exonerated. The showup procedure is included as a legitimate option in the U.S. National Institute of Justice (NIJ) document “Eyewitness Evidence: A Guide for Law Enforcement,” published in 1999, and the Wisconsin Department of Justice's “Model Policy and Procedure for Eyewitness Identification,” released in 2005. Despite the situations in which the potential advantages of a showup might outweigh the otherwise prudent decision to conduct either a live or a photo lineup with nonsuspect fillers, the best practice-recommendation is to think of a lineup as the default procedure. It is not unreasonable, for example, to expect that law enforcement can use current and near-future technology to construct an electronic photo lineup at a crime scene using a digital image of a suspect who was found in the vicinity and benefit from the [Page 366]immediacy associated with the showup and the safeguards associated with a lineup.

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