Study 1
Langley and colleagues (2021) conducted a randomized controlled trial to examine the impact that a procedural justice checklist made on various outcomes involving individuals suspected of terrorism. The study was conducted beginning in March 2016 across 21 ports in a European democracy and involved 65 counterterrorism teams. Teams operated in sea, train, and international ports that handled an estimated 1.5 billion passengers during the year before the trial. These teams were the units of randomization; they were randomized into the treatment group (n = 34 teams), which applied the procedural justice checklist, and the control group (n = 31 teams), which conducted business as usual.
The treatment group consisted of 227 individual counterterrorism officers. Most teams were located in airports (24), but some were in seaports (9) or train ports (1). The control group consisted of 224 individual counterterrorism officers who also worked in air (22), sea (7), and train ports (2). The role of these counterterrorism teams was to stop and search persons suspected of involvement in the commission, preparation, or instigation of terroristic acts. During the study, 1,418 persons of interest were stopped by these teams. Of those persons stopped by the treatment group (n = 803), 85.8 percent were male, 52.6 percent were in a relationship, 33.8 percent had a bachelor’s degree or higher, and 37.4 percent were foreign nationals. Of the persons stopped by the control group (n = 615), 85.5 percent were male, 53.5 percent were in a relationship, 31.6 percent had a bachelor’s degree or higher, and 33.7 percent were foreign nationals. There were no statistically significant differences between the groups in any baseline measures.
The outcomes included measures of distributive justice, effectiveness of counterterrorism, obligation to obey the law, willingness to cooperate with police, and social resistance. Distributive justice, or the perception of fairness in treatment in comparison with what others receive, was measured by four Likert-type items such as "The police treated me the same way any other person would have been treated." Effectiveness of counterterrorism was measured using multiple items with a Likert-type scale such as "The police are too soft on terrorism." Obligation to obey the law was measured by three Likert-type items on a scale of 1 to 5, such as "It is alright to go against the law, if you think the law is wrong." Willingness to cooperate with police was measured by 10 Likert-type items on a scale of 1 to 4, such as "I would report a person I overheard discussing their involvement with terrorism." Social resistance, or willingness and ability to defy a country or dominant group, was measured using multiple items with a Likert-type scale such as "I often find myself objecting to the symbols of my country." A series of linear, logistic, and ordered logit multilevel regression models were used to estimate the effect the procedural justice checklist had on these outcomes. The study did not conduct subgroup analyses.