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 The Census Bureau’s Count Question Resolution (CQR) Program accommodates changes to geographic boundaries reported after the release of the 1990 census data tabulations. Such changes usually are the result of corporate annexation/detachment activity or of updates to published 1990 geographic boundaries. Often these changes have been reported to the Census Bureau by local governments and other data users with a request for review and possible update. (Other post-1990 block changes may result from the needs of the economic censuses and related programs.) The Census Bureau makes postcensal block updates by adding additional suffixes to the census tabulation block number. Figure 11-5 shows a corporate boundary change that splits Block 102A into 102AA and 102AB. This use of a second suffix position in the block number shows that the change resulted from a post-1990 resolution of a count question.

Figure 11-5. Tabulation Block Split as a Result of Count Question Resolution

The relationship of census blocks to other geographic entities depends on several factors. The major factors are the type of geographic entity, the stability of the particular geographic boundary, the coincidence of physical features with the boundary, and enumeration considerations. As explained in the section in this chapter entitled “” (and shown in, , and ), geographic boundaries that cross census collection blocks result in a suffixing of the census 11-16Census Blocks and Block Groups