Identifies the patient's census tract of residence at the time the tumor was diagnosed. Census Tract 70/80/90 is a derived (geocoded) variables based on the Census Boundary files from 1970, 1980, 1990 Decennial Census. See Census Tract 2000 [130]; Census Tract 2010 [135]; Census Tract 2020 [125]. Codes are those used by the U.S. Census Bureau for the Year 1970, 1980 or 1990 Census. Refer to Census Cod Sys 1970/80/90 [120] to ascertain the decade of reference. For consolidated records, the geocoded state should be based on the best address at diagnosis information identified.

Census tract codes allow central registries to calculate incidence rates for geographical areas having population estimates. This field allows a central registry to add Year 2020 Census tracts to tumors diagnosed in previous years, without losing the codes in data items Census Tract 2000 [130]; Census Tract 2010 [135]; Census Tract 2020 [125].

The Census Bureau provides population and other demographic data for census tracts. This allows for small area analysis for general surveillance or special geographical and socioeconomic analysis.

Instructions for Coding

This variable is generated through the process of geocoding either during abstracting or at the central registry level.
Census tract codes have a 4-digit basic number and also may have a 2-digit suffix. Census tract numbers range from 0001.00 to 9999.98, but the decimal should not be retained in the NAACCR layout.
At a minimum, all cases diagnosed through diagnosis year 1999 should have a Census Tract 1970/80/90. Cases diagnosed 1996-1999 must have both State at DX Geocode 1970/80/90 [81] and State at DX Geocode 2000 [82] codes for proper assignment of the Census Tr Poverty Indicatr [145].
If the patient has multiple tumors, geocoded state at diagnosis may be different for each tumor.
Do not update this item if the patient's tract of residence changes. Store updated address information in the affiliated current address data items. Only update based on improved information on the residential address at time of diagnosis. For instance, it is appropriate to correct a tract during manual geocoding or a consolidation process.
PO Box address information should not be used to geocode this data item except in the infrequent case when no other address information is available.
Blank "Not geocoded" is allowable for cases diagnosed after 1999. However, it is recommended to have all cases geocoded to a Census Tract 1970/80/90 to allow for both retrospective and cross-sectional analyses.

000100-999998	Valid FIPS Codes
000000	Area not census-tracted
999999	Area census-tracted, but census tract is not available
Blank	Census Tract 1970/80/90 not coded

Note: For U.S. residents, historically, standard codes are those of the FIPS publication "Counties and Equivalent Entities of the United States, Its Possessions, and Associated Areas." These FIPS codes (FIPS 6-4) have been replaced by INCITS standard codes; however, there is no impact on this variable as the codes align with the system the Census used for each decennial census and changes will automatically be accounted for during geocoding. County codes issued by the Federal Information Processing Standards (FIPS) publication Counties and Equivalent Entities of the United States, Its Possessions, and Associated Areas is available in Appendix A.