A Census Block Group (CBG) is the smallest geographical unit for which demographic data is published, allowing for the most precision and relevance in the market. Typically, Block Groups are very small and include a population of 600 to 3,000 people.  There are 217,740 searchable CBGs in the USA vs 27,797 general zip codes. For every report, Realscore sums the number of practitioners and all demographic data for all of the CBG’s (including partial CBG’s) in the radius, drive time, and/or user-drawn search area.

Click here for an independent third party expert’s advice about why you should not use zip codes for geospatial analysis.