The map provide functions for individual to look up locations and the boundaries of Census Block Group numbers by address or Census Block Group Number. The data resources are based on Esri ArcGIS (www.arcgis.com) and Census Block 2010 Data (www.census.gov/). It covers Census Block's demographic information which are population, race, gender, age, and household. The geocoder which used through the Esri ArcGIS may not be able to provide rooftop accuracy since it is that the addresses are in the range dataset instead of the accurate points. The spatial data may haven't been updated to cause error. You can find additional information .You can find additional information on https://factfinder.census.gov/faces/nav/jsf/pages/searchresults.xhtml?ref=addr&refresh=t#.