DOES WHAT POLICE DO AT HOT SPOTS MATTER? THE PHILADELPHIA POLICING TACTICS EXPERIMENT*

“Opportunity theories (Brantingham and Brantingham, 1991 [1981], 1993; Cohen and Felson, 1979; Felson, 1987) emphasize that the characteristics of places structure the routine activities of individuals and produce criminogenic combinations of of-fenders, targets, and guardianship levels at certain…”

“Incidence rate ratios (IRRs) are exponentiated β coefficients and reflect, after multiplying the difference between the IRR and 1 by 100, the expected percentage change in the predicted count of the outcome variable (Rabe-Hesketh and Skrondal, 2012).”

“…the OF tactic is based on the criminological axiom that a small percentage of offenders is responsible for a disproportionate amount of crime (Esbensen et al., 2010; Wolfgang, Figlio, and Sellin, 1972); however, the success of the OF treatment also has several possible practical explanations.”

“Repeated-measures multilevel models are appropriate for experimental study designs (Bryk and Raudenbush, 1987; Raudenbush and Bryk, 2002).”

“When community members perceive that police actions are fair, they are more likely to be more satisfied with and have confidence in police services, follow the law, and help police fight crime (Reisig and Lloyd, 2009; Taylor and Lawton, 2014; Tyler, 1988, 2004).”

“In many instances, it may be currently impossible to disentangle the true impact of race on crime (Massey and Sampson, 2009), though a recent study by the Center for Policing Equity at the University of California, Los Angeles, suggests that racial disparities in police use of force remain robust after controlling for…”

“Crime mapping is linked to specific theories of crime that are instrumental in understanding crime hot spots, routine activities theory, crime pattern theory, and rational choice perspectives (Groff et al., 2015:62).”

“Some studies have attempted to observe POP versus saturated patrol or components thereof (Groff et al., 2015; Kochel et al., 2015).”

“Past studies have examined methods for the creation of data-informed beat zones including the use of computational and analytical models for solving problems in crime (Sorg et al. 2014; Skog and Tona, 2009; Santos and Taylor 2014).”

“This observation supports the literature indicating that hotspots exhibit short-term stability, typically lasting only a few months (Deckard and Schnell, 2023; Groff et al., 2015).”

“Multivariate analyses have been utilized in previous studies with experimental designs (e.g., Groff et al., 2015; Sorg et al., 2016) and are more appropriate than change models as they account for measurement error and participants’ pretest scores (Bryk & Raudenbush, 1987; Raudenbush & Bryk, 2002).”

“Such a finding stands in contrast to the work of Wood, Sorg, Groff, Ratcliffe, and Taylor (2014) in Philadelphia, where it was found that police using considerable street or local knowledge balanced their crime interventions with social supports.”

“Dallas and Tacoma devoted significant police resources to a hot spots strategy that was based on previous research (Braga et al., 2019; Cor-saro et al., 2019; Groff et al., 2015) and intentionally designed to help reduce violent crime in targeted hot spots.”

“The model could also be framed in terms of other place-based tactics, including problem solving, third-party policing efforts, or the deployment of surveillance technologies (Groff et al. 2015 ; MacDonald et al. 2024), although possibly with different implied time scales.”

“However, POP interventions in practice are often limited due to minimal community partnership efforts, limited agency support and implementation, and heavy reliance on enforcement tactics (Cordner & Biebel, 2005; Groff et al., 2015; Ratcliffe et al., 2015).”

“Researchers have conducted foot patrol experiments in a number of cities, from the Kansas City Preventative Patrol Experiment (Kelling et al., 1974) and the Newark Foot Patrol Experiment (Kelling et al., 1981), to the Philadelphia Policing Tactics Experiment (Groff et al., 2015).”

“The proximate inspiration for CORE was Philadelphia’s offender-focused (OF) policing tactic, the evaluation of which produced evidence that in 2010–2011, OF policing had substantial effects on violent crime in the places in which it was concentrated (Groff et al., 2015).”

“…partnership efforts, limited agency support and implementation (e.g. officers not having enough time or other support to do good problem-solving), and heavy reliance on enforcement tactics (Cordner & Biebel, 2005; Eck, 2006; Groff et al., 2015; Ratcliffe et al., 2015; Weisburd & Braga, 2006).”

“Some described cooperative relationships between a police agency and researchers that contributed to the planning of the research study, whether the relationship was ongoing (Groff, et al., 2015) or a matter of serendipitous timing (Sherman & Rogan, 1995).”

“In these studies the police interacted with offenders on the street in crime hot spots (Groff et al. , 2015), in jail, in the courtroom (Abrahamse et al. , 1991; Martin and Sherman, 1986), at the police department, and/or in other public forums (Braga and Weisburd, 2012).”

“It also forms part of the theoretical mechanism explaining the effectiveness of focused police patrol and problem solving at high-crime microgeographic places, or ‘‘hot spots’’ (e.g. Braga and Bond 2008; Braga et al. 1999, 2014; Groff et al. 2015; Lum et al. 2011; Ratcliffe et al. 2011; Sherman and Weisburd 1995; Skog…”

“RCT Groff et al. (2015) - Foot Patrol Violent incidents 0.”

“3Interestingly, a recent hotspot experiment suggests that the distinction between place-based and offender-based interventions may not always hold in practice (Groff et al., 2015).”

“Patrol strategies, therefore, not only vary in their effects on crime (e.g., Andresen and Lau 2014; Bowers and Hirsch 1987; Esbensen 1987; Groff et al. 2015; Jones and Tilley 2004; Piza and O’Hara 2014; Ratcliffe et al. 2011) and contacts with the public (e.g., Groff et al. 2013; Lundälv et al.…”

“Numerous studies examining the distribution of police in high crime locations have found significant reductions in crime (Gibson et al., 2017 ; Groff et al., 2015 ; Nagin & Weisburd, 2013 ; Ratcliffe et al., 2011 ).”

“Offender-focused strategies within hot spots can reduce crime (Groff et al., 2015).”

“While research has found that utilizing specialized units in these ways can result in lower levels of crime and violence (Groff et al., 2015), they still are controversial as they illustrate the collateral consequences of mass enforcement (Chalfin et al., 2021) that result primarily in people of…”

“While broadly adopted by scholars of crime and place (Groff et al. 2015; Weisburd et al. 2012), street segments as the unit of analysis for identifying hotspots possess two limitations: data loss and variable size.”

“…of various existing police tactics at crime hot spots. these strategies can include foot patrol (ratcliffe et al., 2011), offender-focused policing (groff et al., 2015), directed patrol (mcgarrell et al., 2001; sherman & weisburd, 1995; telep et al., 2014), problem-oriented policing (Braga et al.,…”