Constructing a Time-Invariant Measure of the Socio-economic Status of U.S. Census Tracts

Abstract

Contextual research on time and place requires a consistent measurement instrument for neighborhood conditions in order to make unbiased inferences about neighborhood change. We develop such a time-invariant measure of neighborhood socio-economic status (NSES) using exploratory and confirmatory factor analyses fit to census data at the tract level from the 1990 and 2000 U.S. Censuses and the 2008–2012 American Community Survey. A single factor model fit the data well at all three time periods, and factor loadings—but not indicator intercepts—could be constrained to equality over time without decrement to fit. After addressing remaining longitudinal measurement bias, we found that NSES increased from 1990 to 2000, and then—consistent with the timing of the “Great Recession”—declined in 2008–2012 to a level approaching that of 1990. Our approach for evaluating and adjusting for time-invariance is not only instructive for studies of NSES but also more generally for longitudinal studies in which the variable of interest is a latent construct.