The Importance of Knowing How a Person Became the Suspect in a Lineup and Wrongful Convictions
"The proportion of times that suspects in lineups are factually guilty can be referred to as the “base rate” of guilt. How a person came to be a suspect in a criminal investigation strongly impacts the base rate of culprit presence in identification procedures, yet this issue has received little consideration from either researchers or the criminal justice system. We argue that consideration of base rates is crucial. In cases where the culprit is not previously known to the witness, the base rate of culprit presence in any identification procedure may be low, and thus, the probability that an identified suspect is guilty should be questioned more than when the suspect was known to the witness prior to the crime.
Using the existing body of literature, we (briefly) discuss (1) the role of eyewitness error in wrongful convictions, (2) the issue of base rates, (3) the dangers of using identification procedures such as showups or mug searches prior to a lineup procedure, (4) the likelihood that showups and mug searches will lead to high rates of police apprehending the actual criminal, and (5) how errors made at this stage are more likely when witnesses view multiple suspects prior to lineups. We conclude that identifications obtained in such situations should be treated with caution and require substantial independent evidence of guilt to justify conviction. Lastly, we provide practical considerations for those working within the criminal justice system"
Excerpted from: The Importance of Knowing How a Person Became the Suspect in a Lineup: Multiple Eyewitness Identification Procedures Increase the Risk of Wrongful Conviction by R. C. L. LINDSAY, MICHELLE I. BERTRAND , AND ANDREW M. SMITH.