Expert Testimony: Lineup Identification

An eyewitness identifies the defendant in a show-up, line-up, photo-spread or mug-book.

We provide expert testimony on the factors that affect identification accuracy.

We testify about two general sets of factors that can increase the accuracy of eyewitness identifications, those stemming from the crime itself, and those from the way in which the investigation was carried out.

Crime Characteristics. The negative factors include:

Perception Factors: the witness viewed the crime in poor light, at night, against backlighting, from a great distance, in the fog, or very briefly.

Attention Factors: presence of weapons or gore that narrow attention away from the perpetrator’s features, many people are present, noise, lots of distraction.

Unfamiliarity Factors: perpetrator was a stranger; events were unexpected; cross racial identification was involved.

Post-Event Factors: witness has learned new information after first describing the crime.

Time Factors: long delay between witnessing and reporting, and between reporting and testifying.

Investigation Characteristics. The negative factors include:

Post-Event Factors: witness has learned new information after first describing the crime.

Questioning Factors: misleading, leading, biased or pressure questioning of the witness.

Lineup Construction Factors: fairness of the lineup (do all individuals have an equal chance of being picked based on witness's description), type of lineup (showup, photospread, parade, mug-shot), size of line-up.

Lineup Presentation Factors: lineup instructions (biased or unbiased admonition about responding), presentation of lineup (individuals shown together or successively), non-blind presentation (does the policeman know who the suspect is), multiple presentations (has the witness seen the suspect or picture since the crime).

US Attorney General’s Guidelines for Investigations Involving Eyewitnesses. Eyewitness Evidence: A Guide for Law Enforcement (NCJ 178240, 1999); Eyewitness Evidence: A Trainer's Manual for Law Enforcement (NCJ 188678): Police Lineups: Making Eyewitness Identification More Reliable (NCJ 219604). These guidelines incorporate most of the latest research and contain recommendations for how investigations involving eyewitnesses should be conducted. CLICK HERE here to view the 1999 US Attorney General’s Guidelines to see if the Guidelines have been properly followed in your case.

CLICK HERE to view our latest research publication on the factors that affect the accuracy of eyewitness identifications: Ralph Haber and Lyn Haber (submitted for publication) Eyewitness Accuracy when Making an Identification in a Lineup. This paper documents evidence that eyewitnesses make identification errors 50% of the time when viewing a lineup.