Poster session on Spatial demography

Using geographically weighted regression (GWR), a recent study by Shoff and colleagues (2012) investigated the place-specific risk factors for prenatal care utilization in the U.S. and found that most of the relationships between late or not prenatal care and its determinants are spatially heterogeneous. However, the GWR approach may be subject to the confounding effect of spatial homogeneity. The goal of this study is to address this concern by including both spatial homogeneity and heterogeneity into the analysis. Specifically, we employ an analytic framework where a spatial lagged (SL) effect of the dependent variable is incorporated into the GWR model, which is called GWR-SL. Using this innovative framework, we found preliminary evidence to argue that spatial homogeneity may play a role in the study by Shoff et al. (2012). The GWR-SL approach allows us to gain a better understanding of prenatal care utilization in US counties, and improves on conventional approaches (e.g., OLS and spatial lag models). The new findings help us to better estimate how the predictors are associated with prenatal care utilization across space, and determine the counties whose neighboring prenatal care utilization matters.