Block, Tract, and Levels of Aggregation: Neighborhood Structure and Crime and Disorder as a Case in Point
- Author(s): Hipp, John R
- et al.
This paper highlights the importance of seriously considering the proper level of aggregation when estimating neighborhood effects. Using a unique non-rural sub-sample from a large national survey (the American Housing Survey) at three time points that allows placing respondents in blocks and census tracts, this study tests the appropriate level of aggregation of the structural characteristics hypothesized to affect block-level perceived crime and disorder. A key finding is that structural characteristics differ in their effects based on the level of aggregation employed. While the effects of racial/ethnic heterogeneity were fairly robust to geographical level of aggregation, the stronger effects when measured at the level of the surrounding census tract suggest more far-flung networks are important for perceived crime and disorder. In contrast, economic resources showed a particularly localized effect only evident when aggregating to the block-level and differed based on the outcome: higher average income reduced disorder, but increased crime, likely by increasing the number of attractive targets. And the presence of broken households had a localized effect for social disorder, but a more diffuse effect for perceived crime. These findings suggest the need to consider the mechanisms involved when aggregating various structural characteristics in neighborhood studies of crime rates, as well as the broader neighborhood effects literature.