Urban armed groups, especially criminal gangs, are a growing threat to peace and economic growth in cities across the world, and often exert state-like powers such as enforcing contracts, policing, and taxing businesses. In partnership with the City of Medellín and community officials, researchers are introducing a co-designed program of intensified government outreach and service delivery to test the impact of increased municipal governance on the roles and legitimacy of local gangs and the state.

Policy Issue 

Urban armed groups, especially criminal gangs, are a growing threat to peace and economic growth in cities across the world. Gangs, mafias, and urban militias have turned large portions of many cities into violent hot spots where government officials and police forces do not go. In certain neighborhoods in Latin America and elsewhere, criminal organizations also act as local governing bodies, exerting state-like control over populations that are underserved by the government.

Despite the prevalence of such “criminal governance” in cities around the world, there is very little information available to policymakers about effective strategies to reduce the influence of urban armed groups. Can the state begin to provide everyday governance in place of these unofficial groups, and thereby increase its own legitimacy?

Context of the Evaluation 

After five decades of civil war and drug trafficking conflicts, Colombia has made significant improvements in security across the country.[1] However, urban gangs remain a threat to state authority in poor and historically underserved areas. In Medellín, Colombia’s second largest city, gangs established their power and control in response to an historic lack of government presence and services, as well as the city’s geographic significance to drug trade routes.

Today, a majority of poor and middle-income neighborhoods in Medellín are governed to varying degrees by criminal gangs. Between 150 and 300 local youth gangs called combos, managed and controlled by larger, mafia-like organizations called razones, exert state-like powers such as resolving disputes, enforcing contracts, policing and preventing crime, managing markets, and taxing businesses in their neighborhoods. Combos also monopolize local illegal markets, especially retail drug sales, prostitution, and loan-sharking.

In Medellín’s urban core, the state is relatively strong and well-organized, and the city government provides a variety of public services to all corners of the city. However, in certain areas of the city’s peripheries, state presence is weak and combos are strong.

Details of the Intervention 

In partnership with the City of Medellín and community officials, researchers designed an anti-gang intervention that will increase the role of the city government in providing public services. The intervention was designed after two years of intensive study of combos through hundreds of interviews with community members and leaders, police, combo members, and other criminal leaders. This study will evaluate the impact of this anti-gang policy intervention on the roles and legitimacy of the state and of combos. This will be the first large-scale randomized evaluation of an anti-gang intervention ever conducted.

Medellín is divided into 21 large administrative units called comunas, each of which is further divided into official neighborhoods. Neighborhoods are further divided into informal communities called sectors, which each contain between 1,000 and 3,000 residents. The city identified the eighty sectors where governance by combos is greatest, and researchers randomly assigned forty of these neighborhoods to receive the anti-gang intervention. The other forty neighborhoods will receive the normal amount of outreach and services offered by the government and will serve as the comparison group.

In each sector assigned to the anti-gang intervention, the city government will place a “liaison” who is responsible for advocating for and coordinating government service delivery. Liaisons’ roles include (1) routine problem-solving and dispute resolution, (2) coordinating and intensifying delivery of existing city services such as social welfare or maintenance services, and (3) improving community organizations' ability to obtaining public resources. Under the status quo, the city government assigns one liaison per 120,000 people. In sectors assigned to the anti-gang intervention, the ratio will drop to one liaison per 2,000 people.

The city government will also intensify its regular strategies to govern and deliver public services. A multi-disciplinary team within the city’s Secretariat of Security will work with other city agencies to deliver tailored services to sectors as requested by liaisons. Overall the evaluation will shed light on whether increasing the effectiveness of government service provision can increase the perceived legitimacy of the government and reduce the role of criminal groups in providing public services.

The research team will conduct three surveys of liaisons and community leaders: an initial survey at the beginning of the anti-gang intervention, a second survey one year after the start of the intervention, and the final survey two years after the anti-gang intervention began.

Researchers leveraged this study to examine how gangs and organized crime are responding to the COVID-19 crisis. Read more here.

Results and Policy Lessons 

Project ongoing; results forthcoming. 


Claire Felter and Danielle Renwick, “Colombia’s Civil Conflict,” Council on Foreign Relations, last modified January 11, 2017, https://www.cfr.org/backgrounder/colombias-civil-conflict