An FBI-led, anti-gang strategy in Los Angeles, California, designed to reduce neighborhood-level violent crime through the identification, disruption, and dismantling of violent street gangs. This program is rated Effective. Results indicated a statistically significant 22 percent reduction per month in violent crime between the treatment areas and the comparison areas.
Operation Thumbs Down was an anti-gang strategy implemented in South Central Los Angeles, California, by a Federal Bureau of Investigations (FBI) Safe Streets and Violent Crimes taskforce, comprising federal agents, intelligence analysts, and local law enforcement officers. The goal of the program was to reduce neighborhood-level violent crime through the identification, disruption, and dismantling of violent street gangs. The program targeted the Rollin’ 30’s Harlem Crips, a sect of the Crips gang who operated in the Los Angeles Police Department’s (LAPD’s) Southwest Division in South Central Los Angeles.
The Rollin’ 30’s Harlem Crips were identified by the FBI as being responsible for a large portion of violent crime in LAPD’s Southwest Division. The taskforce conducted covert surveillance into the gang for more than a year, using investigative tools such as surveillance, wiretaps, and the use of proffer agreements, to build a case against key members of the organization’s leadership. The investigation culminated in a takedown on August 29, 2013 and included the following legal actions: 23 federal indictments, 16 federal arrests on the date of the takedown, 24 federal and 2 state warrants issued, 4 probation or parole searches executed; and 18 state arrests on the date of the takedown. Other targeted individuals were either arrested by both federal and local authorities or turned themselves into authorities in the days immediately following the takedown.
After the takedown, taskforce officers briefly initiated a limited number of community initiatives, including community outreach and neighborhood beautification. They also organized a single “community resource day,” which involved 40 community or government groups, healthcare, and behavioral health organizations that distributed information to local residents.
Operation Thumbs Down was based on the FBI’s enterprise theory of investigation (ETI), which is an approach to identify, disrupt, and dismantle violent street gangs through investigation and prosecution (Weisel 2002). ETI combines short-term, street-level enforcement activity with investigative techniques such as consensual monitoring, financial analysis, and Title III wire intercepts (FBI 2016). It requires the identification of a criminal organization, the activities they conduct, and the financial assets they possess.
The program was also closely associated with an intelligence-led policing philosophy (Ratcliffe and Guidetti 2008), which emphasizes analysis and intelligence as pivotal to an impartial, decision-making framework that concentrates on crime hot spots, repeat victims, prolific offenders, and criminal groups. This form of policing enables crime and harm reduction, disruption, and prevention through strategic and tactical management, deployment, and enforcement (Ratcliffe 2016).
Violent crime was reduced by about 4.2 violent crimes per month (a 22 percent reduction) in treatment sites, compared with control sites, following the implementation of Operation Thumbs Down, a statistically significant difference.
Using a quasi-experimental research design, with non-equivalent groups, Ratcliffe, Perenzin, and Sorg (2017) evaluated the impact of Operation Thumbs Down on violent crime in the treatment sites (Rollin’ 30’s turf), compared with control sites of a similar gang set (Rollin’ 60’s Harlem Crips turf) in the Los Angeles Police Department’s (LAPD’s) Southwest Division in South Los Angeles, California.
The treatment area consisted of known Rollin’ 30’s turf, as mapped by the LAPD, an area of about 1.91 square miles. Consistent with crime displacement research (Ratcliffe and Breen 2011), an additional area of approximately two blocks was drawn around the target area to assess immediate spatial crime displacement. The control area, identified by the FBI Safe Streets and Violence Crimes taskforce, was the Rollin’ 60’s gang territory, given its similarities to the Rollin’ 30’s area. Also, the Rollin’ 60’s gang had not been targeted by the taskforce, and they occupied an area of the neighborhood far enough away from the treatment area that any actions taken against the Rollin’ 30’s were unlikely to impact the control area. Demographic data, drawn from the American Community Survey, was used to compare the two areas, and variables examined included race, young male population, household income, and owner-occupied home values. Census data indicated that there were no statistically significant differences between the treatment and control areas in terms of housing tenure, socioeconomic status, and family structure. The racial composition of each area was statistically different. Both treatment and control areas had almost equal percentages of white populations (18 percent and 17 percent, respectively), but the Rollin’ 30’s was primarily Hispanic (63 percent) and the Rollin’s 60’s had a predominately black population (63 percent). However, the study’s approach to using non-contiguous control areas with crime and socioeconomic conditions similar to the target area is consistent with previous research (Papachristos et al. 2007).
A time-series analysis was conducted to examine the effectiveness of Operation Thumbs Down. Multiple years of crime data were used to establish a crime trend over a period prior to the gang takedown and to better incorporate multi-year crime trends into the pre-intervention time series. Crime data was obtained for LAPD from January 2007 to October 2014, which allowed for 80 pre-intervention analysis months, and 14 post-intervention months. The impact of the intervention was estimated using a diffusion-regression state-space model, that infers a causal effect of an intervention by generating a counterfactual prediction of the target area time series, had no intervention occurred (Brodersen et al. 2015). This analytical approach integrated the longitudinal times series from the control site into the analysis of the treatment location, rather than analyzing the control series independently. Bayesian time-series estimations were conducted, using the Causal Impact package, to assess the monthly count of violent crime in the target area, with two predictors of the number of days in each month and the violent crime frequency in the control area. The violent crime outcome included all homicides, rapes, robberies, aggravated assaults, and arson. No subgroup analysis was conducted.
There is no cost information available for this program.
Evidence-Base (Studies Reviewed)
These sources were used in the development of the program profile:Study 1
Ratcliffe, Jerry H., Amber Perenzin, and Evan T. Sorg. 2017. “Operation Thumbs Down: A Quasi-Experimental Evaluation of an FBI Gang Takedown in South Central Los Angeles.” Policing: An International Journal of Police Strategies & Management
These sources were used in the development of the program profile:
Brodersen, Kay H., Fabian Gallusser, Jim Koehler, Nicolas Remy, and Steven L. Scott. 2015. “Inferring Causal Impact Using Bayesian Structural Time-Series Models.” Annals of Applied Statistics
FBI. 2016. Violent Gang Task Forces
Papachristos, Andrew V., Tracey L. Meares, and Jeffrey Fagan. 2007. “Attention Felons: Evaluating Project Safe Neighborhoods in Chicago.” Journal of Empirical Legal Studies 4(2):223–72.
Ratcliffe, Jerry H. 2016. Intelligence-Led Policing.
Ratcliffe, Jerry H., and Clairissa Breen. 2011. “Crime Diffusion and Displacement: Measuring the Side Effects of Police Operations.” The Professional Geographer
Ratcliffe, Jerry H., and Ray Guidetti. 2008. “State Police Investigative Structure and the Adoption of Intelligence-Led Policing.” Policing: An International Journal of Police Strategies & Management
Weisel, Deborah Lamm. 2002. “The Evolution of Street Gangs: An Examination of Form and Variation. In W.L. Reed and S.H. Decker (eds.). Responding to Gangs: Evaluation and Research
. Washington, D.C.: National Institute of Justice, 25–65.