Lineups and photo arrays are often presented to witnesses by police officers who know which lineup member is the suspect (single-blind lineup administration) rather than by officers who do not know (double-blind administration). Administrators who are not blind to which lineup member is the suspect are more likely than blind administrators to emit behavioral cues that steer witnesses toward choosing the suspect and away from choosing fillers (i.e., a lineup member who is not the suspect). Moreover, nonblind administrators may provide confirmatory feedback to witnesses who identify the suspect, increasing their confidence in the accuracy of their identification and weakening the correlation between witness confidence and accuracy. Nonblind administrators are also more likely to interpret witnesses’ tentative statements about a suspect than about a filler as a positive identification. Because of these findings that single-blind administration biases identifications against suspects, even when they are innocent, evidence-based recommendations for best practices in the collection of eyewitness-identification evidence call for the use of double-blind lineup-administration procedures.

阵容和照片阵列通常由知道嫌疑犯的警察（单盲阵容管理）而不是不认识的警察（双盲行政）提供给目击者。与盲目管理员不相识的管理员比盲目管理员更有可能发出行为线索，引导证人选择犯罪嫌疑人，而不是选择补遗（即不是犯罪嫌疑人的成员）。此外，非盲目管理者可能会向确认嫌疑人的证人提供确认性反馈，从而增加他们对其身份识别准确性的信心，并削弱证人信心与准确性之间的相关性。非盲目的管理者也更有可能解释证人关于嫌疑人的初步陈述，而不是将证人作为肯定的身份。由于这些发现，即使是无辜的嫌疑人，单盲管理也会偏向于对犯罪嫌疑人的识别，因此，基于证据的目击者身份识别最佳实践建议基于证据的建议要求使用双盲联盟管理程序。