questionnaire administered to a fraction of households and residents of group quarters. The basic items are also called 100 percent or complete-count items.
This appendix describes the processing of the basic data items for households and persons, focusing on procedures to supply values for missing items (see Titan Corporation, 2003, Sheppard, 2003, and Alberti, 2003, respectively, for detailed information on the steps in data capture, coverage edit and telephone follow-up, and data processing). The Census Bureau distinguishes between “imputation” (or “allocation” in the Bureau’s terminology), in which information from another person or household is used to supply a missing value, and “assignment,” in which a value is assigned on the basis of other information for the same person (e.g., supplying a value for sex on the basis of first name). There is also “editing,” in which inconsistent reported values are reconciled. Sometimes an inconsistent value is deleted and imputation or assignment is used to supply a value for the item. Finally, there is whole-household imputation (or “substitution”), in which an entire household is duplicated for another enumerated household that lacks sufficient information to be termed “data-defined.” For the complete count, a household is data-defined if at least one member has reported values for at least two basic items (including name).
For the 2000 census, data capture of information on questionnaires was performed by optical mark and optical character recognition (OMR/OCR) after the questionnaires were scanned into computer files. Names were captured, along with write-in and checked values. Clerks keyed data items from images when the automated technology could not read the responses. Keying of long-form-sample information was set aside in the processing to permit the fastest possible keying of the basic information, which was captured from both short-form and long-form questionnaires to obtain complete-count records.
After data capture, computer routines reviewed the complete-count records for mail returns (including the small number of Internet and Be Counted returns) to identify cases for telephone follow-up. The workload for the coverage edit follow-up operation totaled