All About FIPS Codes



We will soon be introducing new functionality to CDXZipStream that takes advantage of a unique code assigned to all geographic areas by the U.S. Census Bureau, called the FIPS (Federal Information Processing Standard) code.  CDXZipStream is our Microsoft Excel add-in that performs location analysis for address lists, such as route optimization, zip code radius calculation, and demographics retrieval. 

FIPS codes can be used to accurately identify very small geographies, such as census tract and block areas, and subsequently allow us to retrieve a wealth of demographic, economic, and cultural data from Census Bureau surveys, such as the ten year 2010 Census and American Community surveys.  A major advantage is that both census tracts and blocks are smaller than zip code areas; zip codes on average cover a population of over 9,000, while census tracts are about half that size and census blocks only cover a population of about 100.  As a result, the demographic data for these smaller geographies can provide a much more accurate picture of the population. 

Also, census tracts and blocks are assigned by the Census Bureau, and census data for these areas are fairly precise.   Zip codes are assigned by the U.S. Postal Service, are modified frequently, and must be approximated when applying census data by using ZCTA’s (Zip Code Tabulation Areas).  ZCTA’s are the Census Bureau’s approximate definition of a zip code area that is obtained by aggregating data of census blocks that cover a similar area.  This approximation can introduce additional error in the resulting data.

So what does a FIPS code look like?  For the smallest block geography, it is a 15-digit code that progressively builds upon FIPS codes for state, county, and census tract.  Here’s an example of a block FIPS code for the address 1600 Pennsylvania Avenue, Washington DC :



The FIPS code for the census tract for this address is the first 11-digits (minus the block number), or 11001006202.  Note that when the census tract number is used alone, it will often contain a decimal point, such as 0062.02.  The decimal point is always excluded from the FIPS code.

With the recent 2010 Census and the ongoing American Community Survey, there is now an unprecedented source of extensive, up-to-date demographics data available from the U.S. Census Bureau.   FIPS codes are a very useful key to access this data down to the address level. 

For more information about Census geography, please refer to the following posts:

Census Geography - It's Not Quite What You Learned in School

What's a ZCTA?


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