"Broken windows" theory – the argument that minor forms of public disorder lead to serious crime and a downward spiral of urban decay (Wilson and Kelling, 1982; Kelling and Coles, 1996; Sampson and Raudenbush, 2004).
Ecometrics – a scientific basis for the methodological assessment of human ecological settings, such as neighborhoods and schools.
Neighborhood – a collection of people and institutions occupying a subsection of a larger community.
Neighborhood cluster (NC) – 847 census tracts in the city of Chicago were collapsed to form 343 neighborhood clusters -- an ecological unit of about 8,000 people, large enough to approximate local neighborhoods; respectful of geographic boundaries and knowledge of Chicago's neighborhoods.
Socio-economic status (SES) – defined by a six-item scale that summed standardized neighborhood-level measures of median income, percentage college educated, percentage with household income over $50,000, percentage of families below the poverty line, percentage on public assistance, and percentage with household income less than $50,000 on the basis of the 1990 decennial census. In forming the scale, the last three items were reverse coded.