§ 10.05. Blind or Blinded Procedures

For all identification procedures other than showups, agencies should adopt procedures in which the person administering the identification procedure does not know which person is the suspect. There are two options:

  • (a) blind procedures, in which the person who administers the procedure does not know the suspect; or
  • (b) blinded procedures, in which the person who administers the procedure cannot see which persons or photographs the suspect is examining. This can be accomplished with techniques such as the use of folders, or computerized presentation of images, that shield the images from the person administering the procedure.


a. Blind procedures. A central concern with eyewitness identification procedures is that they can affect or alter the memory of the eyewitness. Officers can do so unintentionally. Indeed, just by asking an eyewitness to participate in an identification procedure, officers create an expectation that a suspect will be present and presented to the eyewitness. An eyewitness naturally will be looking to the officer for guidance, reinforcement, and feedback. Instructing an eyewitness that the officer administering the procedure does not know which is the suspect makes clear at the outset that there cannot be any such guidance, reinforcement, or feedback. As a result, blind or blinded procedures are a crucial protection. Such procedures can minimize the chance that police suggest the desired selection to an eyewitness viewing a live or a photo-array identification procedure. Scientists have long recommended that such procedures be used as an essential feature of the experimental method, to prevent experimenter-expectancy bias.

b. Blinded procedures. Subsection (b) provides alternatives to using an unrelated officer; for smaller agencies, it may be impractical to obtain a second officer unfamiliar with an investigation. To address this practical concern, an eyewitness identification procedure can be “blinded,” even if the administrator is not himself or herself “blind” and unfamiliar with the suspect. One extremely inexpensive way to accomplish blinding is to place the images in folders and shuffle them, so that the eyewitness can examine the images in folders without the administrator being able to see which images are being viewed. A number of jurisdictions and state model policies incorporate this “folder shuffle” method for blinding eyewitness identifications, particularly to facilitate blinded identification procedures among smaller departments that cannot spare officers unfamiliar with investigations. Using computerized presentation of images also can remove the administrator from the process of presenting images to the eyewitness, and can minimize opportunity for suggestion.

Reporters’ Notes

The use of a blind or blinded method is extremely important to the use of any technique designed to test evidence. The use of blinding is “central to the scientific method” because it “it minimizes the risk that experimenters might inadvertently bias the outcome of their research, finding only what they expected to find.” See Nat’l Research Council of the Nat’l Acads., Identifying the Culprit: Assessing Eyewitness Identification 107 (2014). Thus, blinding is essential to any objective factfinding and is central to any type of experiment.

This recommendation is based upon decades of research in a number of fields on the ways in which the expectations of an administrator can bias subjects, including through inadvertent means of communication. “Even when lineup administrators scrupulously avoid comments that could identify which person is the suspect, unintended body gestures, facial expressions, or other nonverbal cues have the potential to inform the witness of his or her location in the lineup or photo array.” Id. at 73. “The ‘blinded’ procedure minimizes the possibility of either intentional or inadvertent suggestiveness and thus enhances the fairness of the criminal justice system.” Id.

It is particularly important to ensure blinding in the context of eyewitness evidence, because eyewitnesses are particularly suggestible. Eyewitnesses naturally may look to law enforcement for guidance and reassurance, and they may be highly motivated to try to reach the answer that an officer thinks is the correct answer. Officers themselves may be motivated to assist the eyewitness in reaching the answer believed to be correct. As the National Academy of Sciences has put it, “[t]he ‘blinded’ procedure minimizes the possibility of either intentional or inadvertent suggestiveness and thus enhances the fairness of the criminal justice system.” See id. at 73; see also Final Report of the President’s Task Force on 21st Century Policing 2.4 (May 2015) (recommending adoption of procedures “that implement scientifically supported practices that eliminate or minimize presenter bias or influence”).

Some in law enforcement have raised concerns regarding the costs of conducting blind procedures. See NRC, Identifying the Culprit, supra, at 107. One common practical concern raised regarding the use of blind procedures is that smaller jurisdictions may not be able to spare an additional officer unfamiliar with an investigation. There is a ready, practical, and cost-effective alternative available for such agencies. The folder-shuffle method is an inexpensive and practical solution. In addition, agencies can use computerized administration of eyewitness identification procedures. See NRC, Identifying the Culprit, supra, at 107. Using folder-shuffle methods or computerized presentation can minimize the costs of using blind or blinded methods. By using blind or blinded methods, agencies can avoid the risks of error created by suggestiveness. And because constitutional rules focus on undue suggestiveness, blind or blinded methods can avert constitutional challenges to eyewitness identification evidence. Indeed, agencies can avert any cross-examination or state-evidence-law challenge to eyewitness evidence by showing that no suggestion could have occurred during an eyewitness identification procedure that was blind or blinded. See NRC, Identifying the Culprit, supra, at 107.

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