Abstract

Evaluation of Census 2010 Block Level Data Using GIS
Track: Census and Statistical Data
Authors: SungHo Ryu, Simon Choi, Jung Seo, Cheol-Ho Lee, SeongHee Min

The decennial census data are key sources of small area socio-economic data for the development of the Regional Transportation Plan (RTP). The 2010 Census block data from PL94 Summary File and Advance GQ Summary File were made available during the 2012 RTP development process since March 2011. There was a concern about the accuracy of the 2010 Census block data. Southern California Association of Governments (SCAG) used various ArcGIS tools such as analysis tools, statistics tools, and data management tools, to identify and confirm the questionable census block level counts of population and housing units. SCAG found around 800 blocks with possible errors and visually confirmed the presence of problematic data by using aerial imagery. Some group quarters population or housing units were assigned to a wrong census block, ramps, major roads, or water bodies. SCAG provided the local jurisdictions with its analysis results and updated the small area dataset.