Figure 11-1. Field Enumeration of a Census Block Prior to 1990
For censuses earlier than 1990, an enumerator was asked to systematically cover that portion of Block 202 within ED 5. This did not include the entire area of Block 202 because a portion, including a housing unit, was within ED 3. The latter requirement often confused enumerators and caused the Census Bureau, in some cases, to miss housing units.
This problem was corrected in the 1990 census when the Census Bureau decided to have enumerators canvass the physical entirety of each block. Proceeding in a clockwise direction, the enumerator identified the location of all housing units to his/her right, and located and indexed these on the enumerator map. The enumerator recorded the street or postal address for each housing unit in the address register within the correct block number. All roads had to be canvassed so that hidden housing units were not missed.
