title: A comparison of least squares regression and geographically weighted regression modeling of West Nile virus risk based on environmental parameters.
abstract: BACKGROUND
  The primary aim of the study reported here was to determine the effectiveness of utilizing local spatial variations in environmental data to uncover the statistical relationships between West Nile Virus (WNV) risk and environmental factors. Because least squares regression methods do not account for spatial autocorrelation and non-stationarity of the type of spatial data analyzed for studies that explore the relationship between WNV and environmental determinants, we hypothesized that a geographically weighted regression model would help us better understand how environmental factors are related to WNV risk patterns without the confounding effects of spatial non-stationarity.
  
  
  METHODS
  We examined commonly mapped environmental factors using both ordinary least squares regression (LSR) and geographically weighted regression (GWR). Both types of models were applied to examine the relationship between WNV-infected dead bird counts and various environmental factors for those locations. The goal was to determine which approach yielded a better predictive model.
  
  
  RESULTS
  LSR efforts lead to identifying three environmental variables that were statistically significantly related to WNV infected dead birds (adjustedR2= 0.61): stream density, road density, and land surface temperature. GWR efforts increased the explanatory value of these three environmental variables with better spatial precision (adjustedR2= 0.71).
  
  
  CONCLUSIONS
  The spatial granularity resulting from the geographically weighted approach provides a better understanding of how environmental spatial heterogeneity is related to WNV risk as implied by WNV infected dead birds, which should allow improved planning of public health management strategies.
authors.affiliation: Advanced Environmental Research Institute and Department of Biological Sciences, University of North Texas , Denton , TX , United States.
authors.forename: Abhishek K
authors.initials: AK
authors.lastname: Kala
authors.affiliation: Advanced Environmental Research Institute and Department of Geography and the Environment, University of North Texas , Denton , TX , United States.
authors.forename: Chetan
authors.initials: C
authors.lastname: Tiwari
authors.affiliation: Advanced Environmental Research Institute and Department of Computer Science and Engineering, University of North Texas , Denton , TX , United States.
authors.forename: Armin R
authors.initials: AR
authors.lastname: Mikler
authors.affiliation: Advanced Environmental Research Institute and Department of Biological Sciences, University of North Texas , Denton , TX , United States.
authors.forename: Samuel F
authors.initials: SF
authors.lastname: Atkinson
keywords: Avian impacts; Emerging infectious diseases; Geographic information systems (GIS); Model comparison; Spatial modeling; West Nile virus