One pattern was more common in Chicago's Hispanic communities and the other in the city's black communities. The five measures of the quality of community life were gang homicide rate, delinquency rate, unemployment rate, percentage living below the poverty level, and mortgage investment per dwelling. Identifying communities as predominantly white, black, Hispanic, or mixed and applying discriminant analysis revealed the racial-ethnic communities as distinct social worlds. Regression analyses of gang homicide and delinquency rates indicated that they display different patterns of association with other community characteristics. An analysis of the residual change score for gang homicide rate over two time periods showed the relative stability of community patterns, with poverty measures explaining much of the change in patterns. The study indicates that gang homicide rates and delinquency rates are ecologically distinct community problems. The distribution of gang homicide rates conforms to classic theories of social disorganization and poverty, and the distribution of delinquency rates is more generally associated with poverty. 10 tables, 3 figures, 67 references. (Author abstract modified)