The 2010 Census Coverage Measurement Program (CCM) conducted an independent listing of housing units in sampled block clusters called the P sample (population sample) of housing units. The P sample was then matched to the 2010 Census address list in the sampled blocks clusters, and the first ring of blocks surrounding the block clusters. The 2010 CCM classified 6,223 of 171,217 of the P-sample housing units in the United States as nonmatches to the 2010 Census address list in the sample block cluster and first ring of surrounding blocks. Of these housing units, 2,030 were classified nonmatches by CCM Estimation because they matched to a housing unit that was deleted from the final 2010 Census address list. The remaining 4,193 housing units were classified as nonmatches because they were missing from the 2010 Census address list.

As a part of the Evaluation of Address Frame and Address Quality, the 4,193 missing housing units were searched for on an expanded address list. The expanded address list included addresses within five kilometers of the sample block cluster, in addition to addresses on the Census Bureau’s Master Address File that were not in the 2010 Census such as addresses listed as businesses.

The number of missing housing units that were matched to the expanded address list is small. Of the 4,193 housing units that CCM classified as missing from the 2010 Census address list, only 150 were found during the matching to the expanded address list, 15 of which were matched to units deleted from the final 2010 Census address list (“census deletes”). Three housing units remained unresolved. The remaining 4,040 housing units persisted as nonmatches, even after expanding the address list geographically and including units not on the 2010 Census address list.

This evaluation looks at the 135 missing housing units that were found in the Evaluation of Address Frame and Address Quality matching to the expanded address list, that were not matched to census deletes. This evaluation reports the level of geography, relative to the CCM search area of the sample block cluster and first ring of surrounding blocks, at which the housing units were found. This evaluation also reports whether the missing addresses were matched to the 2010 Census address list, or to the additional addresses on the Master Address File. Finally, under some basic assumptions about the relationship between person and housing unit matching, this evaluation reports the potential impact of these two types of errors in the address list used in matching on CCM household population coverage estimates.