Incorporating Data Quality Information in Mapping American Community Survey Data

This paper proposes a set of methods to map the American Community Survey (ACS) data disseminated by the U.S. Census Bureau. The ACS replaces part of the original census (long form) in the 2010 decennial Census in the U.S. Reliability of estimates should be taken into account. when analyzing and mapping ACS data because these estimates are derived from surveys with sample sizes much smaller than those in the decennial censuses. Most maps using ACS data do not include data reliability information. In this article, we review the standard data quality or reliability information accompanying the ACS estimates. We propose a set of techniques to map ACS estimates by incorporating the margin of error (MOE) or related information either on the map display or in the mapping process. The techniques are proposed in two contexts: recognizing the varying degree of reliability among estimates, and determining if estimates are statistically different. They offer cartographers anti GIS users some options to map ACS estimates and handle the reliability information simultaneously.