Error and bias in determining exposure potential of children at
school locations using proximity-based GIS techniques. The
widespread availability of powerful tools in commercial
geographic information system (GIS) software has made address
geocoding a widely employed technique in spatial epidemiologic
studies. The objective of this study was to determine the effect
of the positional error in geocoding on the analysis of exposure
to traffic-related air pollution of children at school
locations. For a case study of Orange County, Florida, we
determined the positional error of geocoding of school locations
through comparisons with a parcel database and digital
orthophotography. We used four different geocoding techniques
for comparison to establish the repeatability of geocoding, and
an analysis of proximity to major roads to determine bias and
error in environmental exposure assessment. RESULTS INDICATE
THAT THE POSITIONAL ERROR IN GEOCODING OF SCHOOLS IS VERY
SUBSTANTIAL: We found that the 95% root mean squar