DOI: 10.3886/icpsr34316.v1
title: Reduction of False Convictions through Improved Identification Procedures: Further Refinements for Street Practice and Public Policy, 1983-2010, in five countries.
title: Version 1

description: These data are part of NACJD's Fast Track Release and are distributed as they were received from the data depositor. The files have been zipped by NACJD for release, but not checked or processed except for the removal of direct identifiers. Users should refer to the accompanying readme file for a brief description of the files available with this collection and consult the investigator(s) if further information is needed. This study was a three part project which evaluated the procedural aspects of police lineups. The first part was a meta-analysis of existing laboratory data on comparative eyewitness accuracy rates for sequential versus simultaneous lineups. The second part was three experiments on the elements of current field lineup practices in simultaneous and sequential lineups. The third part was a field experiment in Tucson, Arizona, which tested double-blind simultaneous versus double-blind sequential lineups.
description: The purpose of the study was to enhance the quality and probative value of forensic eyewitness memory evidence acquired through police lineup procedures. The three specific objectives were: To update a meta-analytic review of research comparing simultaneous to sequential lineup formats. ; To conduct controlled laboratory experiments on the impact of three individual lineup procedural components on eyewitness accuracy. The relaxation of the yes/no dichotomous response requirement of the sequential lineup procedure, an appearance change instruction to eyewitnesses, and the use of multiple identification tasks with the same witness. ; The collection and analysis of data in collaboration with the Tucson Police Department, Arizona to compare eyewitness performance on lineup identifications under double-blind simultaneous versus double-blind sequential lineup procedures. ;
description: Meta-Analysis Data The first part of the project was the meta-analysis on comparative eyewitness accuracy rates for sequential versus simultaneous lineups. The studies were chosen on the following three criteria: The study provided a statistical test that compared a sequential to a simultaneous lineup format. ; The statistics required to directly compute a z-test and r (effect size) were available either within the article or from the author. ; The test was for event memory (not a facial recognition paradigm). ; Laboratory Experiments Data The laboratory experiment part of this project investigated three aspects of lineup protocol on the impact on eyewitness memory accuracy. For all three experiments, after a brief introduction the subjects worked through a computer application that requested their demographic information, showed the crime scenario, and provided them with instructions on the upcoming lineup with the experimenter not present. At the end of the crime video, the experimenter re-entered the room and provided additional information corresponding to the particular experiment. Then the subject was shown the lineup with the experimenter in a blinded situation. Laboratory Experiment 1: The relaxation of the Yes/No dichotomous response requirement in the sequential lineup procedure. A 2x2x2 factorial study of three independent variables; perpetrator presence in lineup, lineup format (sequential or simultaneous), and response options for witness (forced choice or not sure option). ; Laboratory Experiment 2: The appearance change instruction. A 2x2x2 factorial study of three independent variables; perpetrator presence in lineup, lineup format (sequential or simultaneous), and inclusion or omission of the appearance change instruction. ; Laboratory Experiment 3: Repeated identification lineups and eyewitness accuracy. A fully crossed randomized 2x2x2 factorial study of three independent variables; lineup format (sequential or simultaneous), common suspect (guilty suspect or innocent suspect) and repeated lineup. Subjects were randomly assigned to four experimental conditions, and each subject completed two lineups separated by approximately two weeks. ; Tucson Arizona Police Department Field Experiment Data The Tucson Police Department constructed a six person computerized photo lineup, with the suspect never in the first position. The computer randomly assigned each witness/lineup to a sequential or simultaneous lineup condition and was shown to the witness at the police station or at a remote location by an administrator who had no knowledge of the suspect.
description: Meta-Analysis Data The Meta-Analysis dataset (n= 72) contains 50 variables on the author, date and published status of the studies, specifications of the lineup experiments, results, and statistical test values. Laboratory Experiments Data The Laboratory Experiment datasets contains variables on the demographics of the subjects, specifications of the experiments, and results of the experiments. The Laboratory Experiment 1: Relaxation of the Yes/No dichotomous response requirement in the sequential lineup procedure dataset (n=378) contains 12 variables. ; The Laboratory Experiment 2: The Appearance Change Instruction dataset (n=702) contains 16 variables. ; The Laboratory Experiment 3: Repeated Identification Lineups and Eyewitness Accuracy dataset (n=305) contains 13 variables. ; Tucson Arizona Police Department Field Experiment Data The Tucson Arizona Police Department Field Experiment dataset (n=76) contains 30 variables on the demographics of the witnesses, type of witness, specifics of the crime, specifications of the experiment, and results of the experiments.
description: Datasets: 
 
 DS1: Dataset
description: computer-assisted self interview (CASI) 
These data are part of NACJD's Fast Track Release and are distributed as they were received from the data depositor. The files have been zipped by NACJD for release, but not checked or processed except for the removal of direct identifiers. Users should refer to the accompanying readme file for a brief description of the files available with this collection and consult the investigator(s) if further information is needed.
The Meta-Analysis Data was collected from studies conducted between 1983 and 2010. The Laboratory experiments and Tucson Police Department Field Experiments Data were collected sometime between 2007 and 2010.
description: Eyewitnesses to Crime in Tucson, Arizona. Eyewitness experiment participants in Canada, Germany, South Africa, United Kingdom, and United States. Smallest Geographic Unit: Country
description: Meta-Analysis Data 49 studies with 72 non-independent tests of sequential versus simultaneous lineup format from 23 different laboratories were chosen. The dataset includes work from 1983 to 2010, representing 13,143 witness-participants, with 55 published and 17 unpublished tests. The original data were collected in Canada, the United Kingdom, South Africa, Germany, and the United States. Laboratory Experiments Data 1,272 participants who were recruited though college research participant pool, on campus advertisements, class announcements, and by word of mouth. Tucson Arizona Police Department Field Experiment Data Tucson Police Department generated 144 lineups, 45.1% sequential and 54.9% simultaneous.