This study constituted a systematic national assessment of local law enforcement perceptions of the distribution of gang and gang-like problems in large cities in the United States, law enforcement reactions to gangs, and their policies toward gang problems. One purpose of the study was to examine changes in law enforcement perceptions of the U.S. gang problem that have occurred since NATIONAL YOUTH GANG INTERVENTION AND SUPPRESSION SURVEY, 1980-1987 (ICPSR 9792) was undertaken. The overall goal was to obtain as "conservative" as possible an estimate of the magnitude of the gang problem in the United States as reflected by the official reaction, record-keeping, and reporting of local law enforcement agencies. The agencies were asked to refer the interviewer to the individual representative of the agency who could provide the most information about the agency's processing of information on gangs and other youth-based groups engaged in criminal activity. To obtain each law enforcement agency's official, not personal, perspective on gang problems, anonymity was intentionally avoided. Each respondent was first asked whether the respondent's agency officially identified a "gang problem" within their jurisdiction. Gangs were defined for this study as groups involving youths engaging in criminal activity. Respondents were then asked if their department officially recognized the presence of other kinds of organized groups that engaged in criminal activity and involved youths and that might be identified by their department as crews, posses, or some other designation. Based on affirmative answers to questions on the officially recognized presence of gangs and the kinds of record-keeping employed by their departments, agencies were sent customized questionnaire packets asking for specifics on only those aspects of the gang problem that their representative had reported the agency kept information on. Variables include city name, state, ZIP code, whether the city participated in National Youth Gang Intervention and Suppression Survey, 1980-1987, and, if so, if the city reported a gang problem. Data on gangs include the number of homicides and other violent, property, drug-related, and vice offenses attributed to youth gangs and female gangs, total number of gang incidents, gangs, gang members, female gang members, and gangs comprised only of females for 1991, number of juvenile gang-related incidents and adult gang-related incidents in 1991, number of drive-by shootings involving gang members or female gang members in 1991, and numbers or percent estimates of gang members by ethnic groups for 1990 and 1991. Respondents also indicated whether various strategies for combating gang problems had been attempted by the department, and if so, how effective each of the crime prevention measures were.

This study was undertaken to enable cross-community analysis of gang trends in all areas of the United States. It was also designed to provide a comparative analysis of social, economic, and demographic differences among non-metropolitan jurisdictions in which gangs were reported to have been persistent problems, those in which gangs had been more transitory, and those that reported no gang problems. Data were collected from four separate sources and then merged into a single dataset using the county Federal Information Processing Standards (FIPS) code as the attribute of common identification. The data sources included: (1) local police agency responses to three waves (1996, 1997, and 1998) of the National Youth Gang Survey (NYGS), (2) rural-urban classification and county-level measures of primary economic activity from the Economic Research Service (ERS) of the United States Department of Agriculture, (3) county-level economic and demographic data from the County and City Data Book, 1994, and from USA Counties, 1998, produced by the United States Department of Commerce, and (4) county-level data on access to interstate highways provided by Tom Ricketts and Randy Randolph of the University of North Carolina at Chapel Hill. Variables include the FIPS codes for state, county, county subdivision, and sub-county, population in the agency jurisdiction, type of jurisdiction, and whether the county was dependent on farming, mining, manufacturing, or government. Other variables categorizing counties include retirement destination, federal lands, commuting, persistent poverty, and transfer payments. The year gang problems began in that jurisdiction, number of youth groups, number of active gangs, number of active gang members, percent of gang members who migrated, and the number of gangs in 1996, 1997, and 1998 are also available. Rounding out the variables are unemployment rates, median household income, percent of persons in county below poverty level, percent of family households that were one-parent households, percent of housing units in the county that were vacant, had no telephone, or were renter-occupied, resident population of the county in 1990 and 1997, change in unemployment rates, land area of county, percent of persons in the county speaking Spanish at home, and whether an interstate highway intersected the county.

This study was the first attempt to investigate gang migration systematically and on a national level. The primary objectives of the study were (1) to identify the scope of gang migration nationally, (2) to describe the nature of gang migration, (3) to assess the impact of gang migration on destination cities, and (4) to describe the current law enforcement responses to the migration of gangs and identify those that appeared to be most effective for various types of migration. Two phases of data collection were used. The major objective of the initial phase was to identify cities that had experienced gang migration (Part 1). This was accomplished by distributing a brief mail questionnaire in 1992 to law enforcement agencies in cities identified as potential gang or gang migration sites. The second major phase of data collection involved in-depth telephone interviews with law enforcement officers in cities that had experienced gang migration in order to develop descriptions of the nature of migration and police responses to it (Part 2). For Part 1, information was collected on the year migration started, number of migrants in the past year, factors that deter gang migration, number of gang members, names of gangs, ethnic distribution of gang members and their drug market involvement, number of gang homicides, number of 1991 gang "drive-bys", and if gangs or narcotics were specified in the respondent's assignment. For Part 2, information was collected on the demographics of gang members, the ethnic percentage of drug gang members and their involvement in distributing specific drugs, and the influence of gang migrants on local gang and crime situations in terms of types and methods of crime, drug distribution activities, technology/equipment used, and targets of crime. Information on patterns of gang migration, including motivations to migrate, drug gang migration, and volume of migration, was also collected. Local responses to gang migration covered information sources, department policies relative to migration, gang specialization in department, approaches taken by the department, and information exchanges and coordination among local, state, and federal agencies.

The goal of this study was to provide useful data on how street gang crime patterns (by amount and type of offense) relate to common patterns of street gang structure, thus providing focused, data-based guidelines for gang control and intervention. The data collection consists of two components: (1) descriptions of cities' gang activities taken from an earlier study of gang migration in 1992, IMPACT OF GANG MIGRATION: EFFECTIVE RESPONSES BY LAW ENFORCEMENT AGENCIES IN THE UNITED STATES, 1992 (ICPSR 2570), and (2) gang structure data from 1995 interviews with police agencies in a sample of the same cities that responded to the 1992 survey. Information taken from the 1992 study includes the year of gang emergence in the city, numbers of active gangs and gang members, ethnic distribution of gang members, numbers of gang homicides and "drive-bys" in 1991, state in which the city is located, and population of the city. Information from the 1995 gang structures survey provides detail on the ethnic distributions of gangs, whether a predominant gang structure was present, each gang structure's typical size, and the total number of each of the five gang structures identified by the principal investigators -- chronic traditional, emergent traditional, emergent integrated, expanded integrated, and specialty integrated. City crime information was collected on the spread of arrests, number of serious arrests, volume and specialization of crime, arrest profile codes and history, uniform crime rate compared to city population, ratio of serious arrests to total arrests, and ratio of arrests to city population.

This study sought to identify and examine current policies and strategies for controlling prison gangs and to determine the ways in which correctional facilities were dealing with gangs in their institutions. Respondents to the mail survey included 55 local jail systems and 52 state prison systems (the 50 state Departments of Corrections, the District of Columbia, and the Federal Bureau of Prisons). The survey question text used the term "security threat group" (STG), which was defined as "two or more inmates, acting together, who pose a threat to the security or safety of staff/inmates and/or are disruptive to programs and/or to the orderly management of the facility/system," rather than the generic term "gang." Data contain information on total inmate population, number of STGs, number of inmates identified as confirmed, suspected, associate, and drop-out members of STGs, total incidents of violence, number of violent incidents by STG members, management strategies to deal with gangs, and names of STGs known to be present within the system.

The 2007 Census of Law Enforcement Gang Units (CLEGU) collected data from all state and local law enforcement agencies with 100 or more sworn officers and at least one officer dedicated solely to addressing gangs and gang activities. Law enforcement agencies are often the first line of response to the gang problems experienced across the country and are a critical component of most anti-gang initiatives. One way for law enforcement agencies to address gang-related problems is to form specialized gang units. The consolidation of an agency's gang enforcement activities and resources into a single unit can allow gang unit officers to develop specific expertise and technical skills related to local gang characteristics and behaviors and gang prevention and suppression. No prior studies have collected data regarding the organization and operations of law enforcement gang units nationwide, the types of gang prevention tactics employed, or the characteristics and training of gang unit officers. This CLEGU collected data on the operations, workload, policies, and procedures of gang units in large state and local law enforcement agencies in order to expand knowledge of gang prevention and enforcement tactics. The CLEGU also collected summary measures of gang activity in the agencies' jurisdictions to allow for comparison across jurisdictions with similar gang problems.

This survey was conducted by the National Youth Gang Intervention and Suppression Program. The primary goals of the program were to assess the national scope of the gang crime problem, to identify promising programs and approaches for dealing with the problem, to develop prototypes from the information gained about the most promising programs, and to provide technical assistance for the development of gang intervention and suppression programs nationwide. The survey was designed to encompass every agency in the country that was engaged in or had recently engaged in organized responses specifically intended to deal with gang crime problems. Cities were screened with selection criteria including the presence and recognition of a youth gang problem and the presence of a youth gang program as an organized response to the problem. Respondents were classified into several major categories and subcategories: law enforcement (mainly police, prosecutors, judges, probation, corrections, and parole), schools (subdivided into security and academic personnel), community, county, or state planners, other, and community/service (subdivided into youth service, youth and family service/treatment, comprehensive crisis intervention, and grassroots groups). These data include variables coded from respondents' definitions of the gang, gang member, and gang incident. Also included are respondents' historical accounts of the gang problems in their areas. Information on the size and scope of the gang problem and response was also solicited.

The research team collected data on homicide, robbery, and assault offending from 1984-2006 for youth 13 to 24 years of age in 91 of the 100 largest cities in the United States (based on the 1980 Census) from various existing data sources. Data on youth homicide perpetration were acquired from the Supplementary Homicide Reports (SHR) and data on nonlethal youth violence (robbery and assault) were obtained from the Uniform Crime Reports (UCR). Annual homicide, robbery, and assault arrest rates per 100,000 age-specific populations (i.e., 13 to 17 and 18 to 24 year olds) were calculated by year for each city in the study. Data on city characteristics were derived from several sources including the County and City Data Books, SHR, and the Vital Statistics Multiple Cause of Death File. The research team constructed a dataset representing lethal and nonlethal offending at the city level for 91 cities over the 23-year period from 1984 to 2006, resulting in 2,093 city year observations.

This subsample of the national crime surveys consists of data on personal and household victimization for persons aged 12 and older in 26 major United States cities in the period 1972-1975. The National Crime Surveys were designed by the Bureau of Justice Statistics to meet three primary objectives: (1) to develop detailed information about the victims and consequences of crime, (2) to estimate the numbers and types of crimes not reported to police, and (3) to provide uniform measures of selected types of crimes in order to permit reliable comparisons over time and between areas. The surveys provide measures of victimization on the basis of six crimes (including attempts): rape, robbery, assault, burglary, larceny, and motor vehicle theft. The total National Crime Survey employed two distinct samples: a National Sample, and a Cities Sample. The cities sample consists of information about victimization in 26 major United States cities. The data collection was conducted by the United States Census Bureau, initial processing of the data and documentation was performed by the Data Use and Access Laboratories (DUALabs), and subsequent processing was performed by the ICPSR under grants from the Bureau of Justice Statistics (BJS). This Cities Attitude Sub-Sample study also includes information on personal attitudes and perceptions of crime and the police, the fear of crime, and the effect of this fear on behavioral patterns such as choice of shopping areas and places of entertainment. Data are provided on reasons for respondents' choice of neighborhood, and feelings about neighborhood, crime, personal safety, and the local police. Also specified are date, type, place, and nature of the incidents, injuries suffered, hospital treatment and medical expenses incurred, offender's personal profile, relationship of offender to victim, property stolen and value, items recovered and value, insurance coverage, and police report and reasons if incident was not reported to the police. Demographic items cover age, sex, marital status, race, ethnicity, education, employment, family income, and previous residence and reasons for migrating. This subsample is a one-half random sample of the Complete Sample, NATIONAL CRIME SURVEYS: CITIES, 1972-1975 (ICPSR 7658), in which an attitude questionnaire was administered. The subsample contains data from the same 26 cities that were used in the Complete Sample.

This data collection examines gang and non-gang homicides as well as other types of offenses in small California jurisdictions. Data are provided on violent gang offenses and offenders as well as on a companion sample of non-gang offenses and offenders. Two separate data files are supplied, one for participants and one for incidents. The participant data include age, gender, race, and role of participants. The incident data include information from the "violent incident data collection form" (setting, auto involvement, and amount of property loss), and the "group indicators coding form" (argot, tattoos, clothing, and slang terminology).