Reduction of False Convictions through Improved Identification Procedures: Further Refinements for Street Practice and Public Policy, 1983-2010, in five countries. (ICPSR 34316)

Principal Investigator(s): Steblay, Nancy, Augsburg College

Summary:

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.

Access Notes

  • 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.

  • One or more files in this data collection have special restrictions ; consult the restrictions note to learn more. You can apply online for access to the restricted-use data. A login is required to apply.

    A downloadable version of data for this study is available however, certain identifying information in the downloadable version may have been masked or edited to protect respondent privacy. Additional data not included in the downloadable version are available in a restricted version of this data collection. For more information about the differences between the downloadable data and the restricted data for this study, please refer to the codebook notes section of the PDF codebook. Users interested in obtaining restricted data must complete and sign a Restricted Data Use Agreement, describe the research project and data protection plan, and obtain IRB approval or notice of exemption for their research.

    Any public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.

Dataset(s)

Dataset - Download All Files (1.254 MB)
Documentation:
Download:

Study Description

Citation

Steblay, Nancy. Reduction of False Convictions through Improved Identification Procedures: Further Refinements for Street Practice and Public Policy, 1983-2010, in five countries.. ICPSR34316-v1. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2016-04-28. https://doi.org/10.3886/ICPSR34316.v1

Persistent URL: https://doi.org/10.3886/ICPSR34316.v1

Export Citation:

  • RIS (generic format for RefWorks, EndNote, etc.)
  • EndNote XML (EndNote X4.0.1 or higher)

Funding

This study was funded by:

  • United States Department of Justice. Office of Justice Programs. National Institute of Justice (2007-IJ-CX-0046)

Scope of Study

Subject Terms:    eyewitness memory, witness credibility, witnesses

Smallest Geographic Unit:    Country

Geographic Coverage:    Arizona, Canada, Germany, South Africa, Tucson, United Kingdom, United States

Time Period:   

  • 1983--2010 (Metadata-Analysis Dataset)

Date of Collection:   

  • 1983--2010 (Metadata-Analysis Dataset)

Unit of Observation:    Individual, Studies

Universe:    Eyewitnesses to Crime in Tucson, Arizona. Eyewitness experiment participants in Canada, Germany, South Africa, United Kingdom, and United States.

Data Type(s):    aggregate data, experimental data, observational data

Data Collection Notes:

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.

Methodology

Study Purpose:   

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:

  1. To update a meta-analytic review of research comparing simultaneous to sequential lineup formats.
  2. 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.
  3. 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.

Study Design:   

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.

Sample:   

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.

Time Method:    Cross-sectional

Mode of Data Collection:    computer-assisted self interview (CASI)

Data Source:

Tucson Police Department, Arizona

Description of Variables:   

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.

Version(s)

Original ICPSR Release:   2016-04-28

Utilities

Metadata Exports

If you're looking for collection-level metadata rather than an individual metadata record, please visit our Metadata Records page.

Download Statistics