Procedural justice theory was introduced almost 30 years ago by Tyler (1980), who proposed that the public is more likely to perceive the police as a legitimate authority if it believes it is treated fairly by the police (Tyler, 1990). There are four dimensions of procedurally just policing that officers should adopt when interacting with the public: neutrality (impartiality in decision making and equal treatment), voice (giving citizens an opportunity to tell their side of the story and provide suggestions for addressing problems), respect (treating citizens with dignity), and accountability (giving reasoned explanations for the decisions officers make; Van Craen & Skogan, 2017). The report highlights two aspects of procedural justice: internal and external.

Research supports the benefits of procedural justice on police-community relationships. For example, according to Reisig’s (2007) survey, citizens who judge police practices as fair and respectful are more willing to participate in crime prevention programs. Mazerolle et al. (2012) conducted a randomized controlled trial in which they found that citizen perceptions of police were more positive when officers conducted traffic stops according to a script based around the four dimensions of procedural justice. Once the public confers legitimacy on police officers, they will be more likely to obey officer instructions out of a sense of ‘moral duty’ (Jackson et al., 2012). Murphy (2017) proposed that procedural justice improves police-community relationships by promoting identification with authorities and reducing the negative emotions attributed to them. Inversely, low procedural justice and unfair treatment of the public may result in negative emotions at a population level, public noncompliance and retaliatory behavior, and the corresponding police reaction and loss of trust in the public.

At the same time, research on procedural justice training and its effectiveness for improving policing outcomes is limited. Wood and colleagues (2020) examined officers’ participation in the Chicago PD procedural justice training and consequent records of complaints regarding the officers’ conduct, settlement pay-outs following civil litigation, and mandatory officer-filed use-of-force reports. They found that the training was successful in reducing all three. Importantly, the impact of training on complaints and use-of force-was resilient, lasting at least two years. A 2019 meta-analysis by Colin and Glenn suggested that improving civilian perceptions of police fairness is not only an important measure of police effectiveness, but also appears to play a role in the police’s ability to control crime as civilian cooperation is highly important for gathering critical crime-related information. Currently, the National Police Foundation is conducting a multi-site hot spots field experiment examining whether procedural justice training affects officer behavior and enhances civilian perceptions of police legitimacy. These and other recent emerging studies on procedural justice signify the ongoing and timely interest for research in this area.

 Research from the mental health field has attempted to provide a de-escalation model that is applicable to law enforcement, describing it as an approach to police-community encounters that draws from procedural justice principles and focuses on de-escalating or preventing further escalation of potential force encounters (Krameddine et al. 2013). Engels and colleagues (2020) determined that de-escalation in policing context refers to a “process or tactics used to prevent, reduce, or manage behaviors associated with conflict, including verbal or physical agitation, aggression, violence, or similar behaviors, during an interaction between two or more individuals.” (pg. 724).

De-escalation has also been endorsed by law enforcement leadership groups. The Police Executive Research Forum (PERF) developed the Integrating Communications, Assessment, and Tactics (ICAT) training, which was designed to handle persons in crisis and teach officers de-escalation tactics as well as critical thinking skills for the management of potentially volatile police-citizen encounters. The IACP also included de-escalation alternatives in their 2020 consensus on police use of force report. Moreover, the adoption of de-escalation training within police agencies appears to be widespread. In a national survey of police agencies (N = 155), a majority of agencies reported currently providing de-escalation training in some form to their officers (CBS News, 2019). However, de-escalation training curriculums can substantially vary (e.g., ICAT, Verbal Judo, and Tact, Tactics, and Trust to name a few; Engel et al., 2020).

Despite its growing popularity, research on the effectiveness of de-escalation training is quite limited. One study evaluated the Tact, Tactics, and Trust Training in two police departments, Fayetteville (NC) Police Department and the Tucson (AZ) Police Department. While the study found the training to improve officers’ attitudes by placing higher priorities on procedurally fair communication during hypothetical officer-citizen encounters, the authors found no evidence that the training led to a reduction in use of force incidents (McLean et al., 2020). Engel and colleagues (2020) conducted a study with the Louisville (KY) Metro Police Department, examining the effects of the ICAT training. Similar to McLean and colleagues’ findings, ICAT training was successful in changing officers’ attitudes, however, they also found initial evidence for de-escalation training reduced the frequency of use of force. Evidence in the literature thus far emphasizes the need for further research examining if and how de-escalation training changes the frequency and severity of police use-of-force.

According to a 2018 Police Executive Research Forum (PERF) survey of law enforcement agencies, a few agencies began to adopt BWCs in 2007 but adoption of the technology began to significantly increase after 2010. By 2016, the Bureau of Justice Statistics (BJS) found that nearly half of all law enforcement agencies in the United States had acquired BWCs, including about 80 percent of the largest local police departments (Hayland, 2018). Many police agencies have continued to adopt BWCs, albeit more recently for some police departments—particularly smaller departments—have chosen to not adopt or end their use of the technology because of the high cost to store and manage BWC footage (Kindy, 2019).

Because the technology is somewhat new, the literature on BWCs is rather limited. Thus, as Crow and colleagues (2017) argued, much of the advocacy for widespread implementation of BWCs, including the Report’s, is based on anecdotal evidence and limited research of varying levels of quality. Researchers have indeed expressed caution in interpreting results due to technical, political, and administrative challenges (Sousa et al., 2016; see Crow et al., 2017). Moreover, the evidence has been mixed. Some studies found BWCs to be associated with reductions in use-of-force incidents and citizen complaints (Hung et al., 2016; Katz et al., 2014; Miller et al., 2014), while other studies did not (Yokum et al., 2019). Besides, although data suggests that the public generally sees BWCs as a positive addition and have high expectations for them, there is less positivity among non-White and younger people (Crow et al., 2017; National Police Foundation, 2020). More research is clearly needed to disentangle the effects of wearing of BWCs on procedural justice practices and public perceptions. However, it has been argued that BWCs alone do not increase the public’s trust, rather their effectiveness depends on the adoption of other community policing and procedural just practices (Ripley & Williams, 2017).

Beyond BWCs, police organizations have begun to adopt—and scholars have begun to analyze—additional types of technology that were not prominent in 2015. For example, unmanned aircraft systems (or drones), virtual reality, artificial intelligence, and facial recognition software (Joh, 2018). While research on these technologies remains even more scarce than research on BWCs, evidence thus far shows that communities tend to react apprehensively to police’ incorporating new technologies, especially when privacy issues are of concern. It is imperative that, as the Report recommended, agencies respond with clear policies on the implementation of technology and actively address the communities’ concerns regarding its use (Bradford et al., 2020; Heen et al., 2017).

Implicit bias can partially explain the disproportionate levels of police intervention toward ethnic/racial minorities. Minorities are more likely to be searched (Langton & Durose, 2013), stopped in traffic and as pedestrians (e.g., Gelman et al., 2007), arrested (Kochel et al., 2011), and there is some evidence that suggests they are more likely to be subjected to use of force (Terrill & Mastrofski, 2002). For example, experimental research has consistently found that there is a Black-crime implicit bias, whereby people unconsciously link Blacks to crime and violence (Correll et al., 2007a, 2007b; Eberhardt et al., 2004). When applied to policing, this Black-crime bias could mean that Black subjects’ ambiguous behaviors are interpreted as more aggressive, and therefore seen as a greater threat, which in turn may lead to receiving greater force (Fridell & Lim, 2016). It must be noted that field research on the topic has generated mixed results. Some studies have not found such effects of race bias on police use of force (e.g., Cesario et al., 2019; Klinger, 2009), while others have (e.g., Gau et al., 2010; Nix et al., 2017; Tregle et al., 2019).

Addressing implicit racial bias is at the forefront of police reform conversations, and proposed solutions include providing police with implicit bias training. The idea is that through training, officers will become aware of potential implicit biases and actively work on preventing them from manifesting into discriminatory behaviors. Many law enforcement agencies across the US have implemented some sort of bias training (CBS, 2019), and there is some evidence that officers are receptive to the trainings (e.g., Principled Policing Training Report). In 2020, Worden and colleagues published an assessment of the NYPD’s implicit bias awareness training, which consisted of 8-hours and used the Fair and Impartial Policing (FIP) curriculum. Results showed that, in the short-term, training increased the level of officers’ knowledge about implicit bias and its potential implications for policing. Importantly, the long-term effects of training, and whether they lead to actual changes in biased behavior, remains unknown.

Recent data suggest that officer wellness is starting to be recognized as a priority. A 2019 survey of 438 law enforcement agencies across the United States found that almost all responding agencies provided mental wellness resources and information, as well as offered an employee assistance program (EAP; Bonner & Crower, 2019). However, Bonner and Crower (2019) found that few agencies provided annual mental wellness checks or resiliency training. The need and effectiveness of preventative mental health checks has been discussed by Spence and colleagues (2019), who reasoned that the high levels of occupational stress, suicide ideation, and substance use known among police officers renders them as a higher risk population who may benefits from proactive regular checks. Nonetheless, there is yet to be in-depth research conducted on the benefits of or the most effective methods for implementing mental health check programs (Spence et al., 2019). Moreover, promoting an organizational culture that normalizes seeking mental health services remains difficult. Mental health services are often underutilized by police officers (Tucker, 2015), and, relatedly, the stigma within law enforcement against seeking mental health support remains pervasive (Spence et al., 2019; Velazquez & Hernandez, 2019). Thus, effective strategies for promoting officer health and wellness through de-stigmatization at the organizational level are greatly needed.

Since the Report, studies have added to the literature on officer safety. For example, in 2020, Wolfe and colleagues contributed to the literature on officer seat belt use, noted by the Report as a leading cause of officer fatalities. The study identified factors for improving officer driving safety, including the need for supervisors to enforce seat belt use (Wolfe et al., 2020). Additionally, the LEO Near Miss Reporting System—endorsed by the Report as a means to collect lessons learned to help shield officers from future accidents, injuries, and fatalities—has continued to compile and share reports on “near misses,” which are associated with improved safety (Thoroman et al., 2018). Other publications have endorsed the Report’s suggestion of providing officers with tactical first aid kits and training to support officer and community safety (Office of Health Affairs, 2015).

Concurrently, in recent years, agencies have increasingly conducted their own examinations of officer wellness within their own agencies, with many acknowledging those cultural challenges that have historically prevented officers from seeking mental health and wellness support. In 2019, 26 agencies across the Commonwealth of Virginia participated in a first responder survey led by the Fairfax County, VA Police Department to identify factors challenging the mental health of officers and inform changes in wellness and suicide prevention strategies (Carson et al., 2019). Three out of ten of first responders indicated not seeking the help they need because of the stigma associated with doing so. Following officer suicides, the Office of the Inspector General for the New York Police Department (NYPD) conducted an investigation of NYPD’s officer wellness and safety services, in part based on a survey of uniformed personnel who retired in 2016. This survey revealed valuable information on cultural challenges to service access and led to recommendations that the NYPD has adopted to build on their existing programming, such as through additional training and the hiring of full-time licensed mental health professionals (Garnett & Eure, 2019).

Others have identified the Report’s challenges in dissemination and widespread implementation. Trautman (2016) noted that offering recommendations alone makes it difficult to determine whether they are implemented at the agency-level. Robinson (2020) identified several obstacles that hindered the Report’s implementation, including the de-centralized nature of policing, the resistant-to-change police culture, gaps in policing research, and the lack of support from some governmental agents. Similarly, Gill and colleagues (2017) speculated about challenges to the dissemination momentum of the Report’s recommendations over time. In particular, given the politicized circumstances surrounding the Report, some have observed that the change in presidential administrations in 2017 may have hampered the speed and scale of law enforcement’s adoption of the Report’s concepts (Gill et al., 2017).

Assessing whether the Report has led to improved changes in policing outcomes has proved challenging. This difficulty is due to several reasons. First, the Report provided an array of recommendations, ranging from the readily implementable (revising use-of-force policies, collecting systematic data on police shootings) to bigger-picture cultural changes (diversifying police forces, shifting away from what the report describes as a “warrior” mindset to that of a “guardian”). Recommendations in the former category are indeed easier to gauge. For example, a survey of 47 of the largest law enforcement agencies in the United States from 2015 to 2017 revealed that 39 percent of the departments changed their use-of-force policies and revised their training to incorporate de-escalation (Stephens, 2019). Cultural changes, and the consequences of such changes, are more difficult to assess. Not only are they long-term changes but it is impossible to not be impacted by the ever-changing socio-political climate surrounding the support, or lack of, of the police institution. Adding to that challenge is perhaps Report’s most salient limitation, and that is the lack of evidence-based guidance for implementing some of its key recommendations. For example, James (2017) noted that while the Report recommended implicit bias training as a best practice, it did not provide specifics on what the training should entail, how it should be administered, and little data exists about the effectives of training. Nonetheless, because it was recommended, numerous agencies have adopted and invested resources in implicit bias trainings that have yet to be systematically validated.

A significant task for future research is to continue producing evidence on concepts such as de-escalation, diversity training, the impact of BWC’s on police-community relationships, and the effects of community policing on crime reduction, among others. Future research must also develop suitable ways to assess police trainings, not only as related to the content but also the most effective formats and modes for teaching, reception, and information retention. Future studies will also need to focus on evaluation of training programs, particularly as it relates to developing national protocols that can supplement the Report’s current recommendations.

Overall, the Report highlighted important areas of policing that academics, practitioners, and policy makers need to push forward and continue to address. As the Report itself described, “Expanded research and data collection are . . . necessary to knowing what works and what does not work, which policing practices are effective and which ones have unintended consequences.” Spivak, McGough, and Rodriguez (2016) noted that the Report offers a “starting point” for practitioners and researchers to implement reforms based on evidence-based practices, but continuous research and implementation of recommendations based on that research is necessary to improve police policies and operations in practice. Ultimately, many have acknowledged the Report’s role in calling attention to issues in policing—emphasizing its call for more research to continue to inform the conversation.