Alternate Name	Item#	Length	Source of Standard	Column #
Census Tract/Block Numbering Area (BNA) (SEER) Census Tract	110	6	SEER	159-164

Description
Code for the census tract or BNA of the patient's residence at the time of diagnosis. SEER used this field for tumors reported before 1998. If the patient has more than one tumor, the codes may be different for each tumor.

Codes are those used by the U.S. Census Bureau. Census Bureau codes for BNA also are entered in this field.

Both census tracts and BNAs have a 4-digit basic number and also may have a 2-digit suffix. Census tract numbers range from 0001.00 to 9499.99. BNA numbers range from 9501.00 to 9989.99. See the Census Bureau's "Area Classifications" for further details.

Rationale
Allows central registries to calculate incidence rates for geographical areas having population estimates. The Census Bureau provides population data for census tracts. Those rates can be used for general surveillance or special geographical and socioeconomic analysis.

Codes

Census Tract Codes	000100-949999
BNA Codes	950100-998999
000000	Area not census-tracted
999999	Area census-tracted, but census tract is not available
Blank	Census Tract 1970/80/90 not coded

Clarification of NPCR Required Status
Information on census tract, census tract certainty, and census tract coding system is required. Tumors diagnosed in 2003 or later, must be coded to the 2000 census definitions and recorded in Census Tract 2000 [130] and Census Tr Certainty 2000 [365]. Tumors diagnosed in 2002, or before must be coded to the 2000 census tract definitions OR to 1990 definitions OR to both the 2000 and 1990 census definitions. Census tract, census tract certainty and census tract coding system should be recorded in the year appropriate data item fields. For tumors diagnosed between January 1, 1998, and December 31, 2002, (inclusive) use of the 2000 census tract definitions is recommended.