Eyewitness Identification: Other Variables That Can Affect Validity

Other variables that might affect the validity of either type of lineup:

• Whether the person administering the lineup is "blind" (does not know which person in the lineup is the suspect).
• The instructions given to the witness, including saying that the suspect "might or might not be present."
• Use of lineup "fillers" who do not resemble the suspect, thus making the suspect stand out. For example, the suspect has dark hair, but only one of five people in the lineup has dark hair. 
• Events that occurred during the incident, such as the use of a weapon that can distract the witness from the suspect's face.

Learn more from the NIJ Journal article "Police Lineups: Making Eyewitness Identification More Reliable."