Examining how lineup practices of Canadian and U.S. police officers adhere to their national best practice recommendations

Canadian (N = 117) and U.S. (N = 167) police officers completed a survey about their lineup construction and administration practices. We compared their responses to the respective national best-practice recommendations (BPRs) in place at that time; the two nations had five similar and four different recommendations. We predicted that if officers' lineup practices were to correspond with best-practice recommendations, officers' reports of their practices should be similar when national BPRs were similar, and differ in line with their country's BPRs when BPRs differed. We generally found the predicted pattern of results. Findings were especially striking when the BPRs differed. Some practices were largely in line with BPRs (e.g., double-blind testing), others corresponded to some extent (e.g., sequential lineups), and others were largely not followed (e.g., informing witnesses that it is as important to exonerate the innocent as it is to convict the guilty). However, even though our hypotheses were generally supported, there was considerable variation in practices that did not correspond with BPRs. We interpret these findings as demonstrating that
BPRs have some influence on practices. Our findings illustrate the importance of assessing user reactions to BPRs and examining barriers to implementation of BPRs. The findings also indicate that BPRs can influence practice but demonstrate that, in the absence of the stronger action of setting legally binding policies, considerable departure from BPRs occurs.