Understanding Police Gang Data at the Aggregate Level: An Examination of the Reliability of National Youth Gang Survey Data (Research Note)

Abstract

The National Youth Gang Survey (NYGS) is an annual survey of a nationally representative sample of police agencies administered by the National Gang Center that provides data on the number of gangs, gang members, and gang homicides across jurisdictions. The focus of the current study is the reliability of key measures of gang behavior measured by the NYGS. Specifically, the current study assesses NYGS data from 2005 to 2009 in terms of missing data, test-retest reliability, internal consistency reliability, and inter-observer reliability. Results showed low levels of missing data for number of gangs and number of gang homicides in jurisdictions with fewer than 200,000 people, while measures of number of gang members and gang homicides in jurisdictions over 200,000 people had missing data from about 30% of participating jurisdictions. The findings also suggest that the NYGS data on gangs and gang members are generally highly reliable. Data on gang homicides also exhibited a high degree of reliability, but only for jurisdictions with populations over 200,000. Implications of the findings and recommendations for future research are discussed.