A simple checklist, that is all it takes: a cluster randomized controlled field trial on improving the treatment of suspected terrorists by the police

Change log
Langley, Brandon 
Ariel, Barak 
Tankebe, Justice 
Sutherland, Alex 
Beale, Marcus 

Abstract: Objectives: When it comes to interviewing suspected terrorists, global evidence points to harsh interrogation procedures, despite the likelihood of false positives. How can the state maintain an effective counterterrorism policy while simultaneously protecting civil rights? Until now, the shroud of secrecy of “national security” practices has thwarted attempts by researchers to test apparatuses that engender fair interrogation procedures. The present study aims to test one approach: the use of a “procedural justice checklist” (PJ Checklist) in interviews of suspected terrorists by counterterrorism police officers in port settings. Methods: Using a clustered randomized controlled field test in a European democracy, we measure the effect of implementing Procedural Justice (PJ) Checklists in counterterrorism police settings. With 65 teams of officers randomly-assigned into treatment and control conditions, we compare post-interrogation surveys of suspects (n = 1418) on perceptions of legitimacy; obligations to obey the law; willingness to cooperate with the police; effectiveness of counterterrorism measures; distributive justice; feelings of social resistance to the state; and PJ. A series of multi-level linear, logistic, and ordered logit regression models are used to estimate the treatment effect, with Hedges’ g and odds ratios used for effect sizes. Results: When compared with control conditions, implementing a policy of PJ Checklist causes statistically significant and large enhancement in all measured dimensions, including the willingness of suspects to obey the law (g = 1.022 [0.905, 1.138]), to cooperate with the police (g = 1.118 [0.999, 1.238]), distributive justice (g = 0.993 [0.880, 1.106]), effectiveness (g = 1.077 [0.959, 1.195]), procedural justice (g = 1.044 [0.930, 1.158]), and feelings of resistance towards the state (g = − 0.370 [− 0.259, − 0.482]). Conclusions: PJ checklists offer a simple, scalable means of improving how state agents interact with terrorism suspects. The police can use what is evidently a cost-effective tool to enhance legitimacy and cooperation with the police, even in a counterterrorism environment.


Funder: University of Cambridge

Article, Procedural justice checklist, Randomised controlled trial, Scalable interventions, Counterterrorism, Legitimacy
Journal Title
Journal of Experimental Criminology
Conference Name
Journal ISSN
Volume Title
Springer Netherlands