U.S. Census Bureau

Appendix A

Census 2000 Dress Rehearsal Overview

The Census 2000 Dress Rehearsal is the culmination of the Census 2000 testing program which began shortly after the 1990 Census was completed. It was conducted in Columbia, South Carolina and eleven surrounding counties; Menominee County, Wisconsin; and Sacramento, California. Each dress rehearsal site was selected because of its demographic and geographic characteristics to provide experience with some of the expected Census 2000 environments. Each site is using a different mix of census and statistical procedures. The dress rehearsal will provide information to assess procedures used in the individual sites but not for comparisons between sites.

Site Selection

The Columbia, South Carolina site includes the city of Columbia in its entirety, including a small portion in Lexington County; the entire town of Irmo, which is in Richland and Lexington Counties; and the following 11 contiguous counties in North Central South Carolina.


This site was selected because it contains living situations and socioeconomic characteristics that are not found in a predominately urban environment. The site provides the only opportunity to test procedures for developing the census address list in an area containing a mixture of house number/street name and rural route and box number addresses. Since this site has a relatively high proportion of African Americans, it provides an opportunity to test Census 2000 procedures for reducing the differential undercount for this racial group. The site selected represents the size of typical local census offices planned for Census 2000, which was necessary to provide an understanding of the effectiveness of census operations.

The Menominee County, Wisconsin site includes the Menominee American Indian Reservation. This site was selected because of the Menominee Reservation. A very high proportion of the population living on the Reservation are American Indians. Also, the Census Advisory Committee on the American Indian and Alaska Native Populations recommended the Menominee Reservation. Conducting the dress rehearsal on an American Indian reservation allows for the testing of Census 2000 methodologies for reducing the differential undercount for reservations, which was estimated to exceed 12 percent in the 1990 Census.

The Sacramento, California site was selected because it contains great diversity among racial and ethnic groups. Selecting a site with a diverse population provides the opportunity to test Census 2000 methods designed to reduce the differential undercount and produce an accurate census for all components of the population. Sacramento is a primary media market, which allowed a full test of the paid promotion program. Also, this site represents the size of typical urban local census offices planned for Census 2000, which allowed for an understanding of the effectiveness of census operations in this type of office.

The relative sizes of each of the sites are estimated to be:

  Sacramento South Carolina Menominee
Housing Units 153,000 252,000 1,700
Population 374,000 667,000 4,600

Methodology by Site

The Dress rehearsal involved operational testing of the Headquarters, Regional Census Center, Local Census Office, and Data Capture Center procedures and systems in a census-like environment. Several procedures new and enhanced since the 1990 Census, such as user-friendly forms, digital capture of forms, statistical sampling and estimation, and paid advertising, were tested individually prior to the Dress rehearsal.

  Sacramento South Carolina Menominee
Mailout/mailback X X  
Update/leave/mailback   X X
100% Nonresponse followup   X X
Sample Nonresponse followup X    
Integrated Coverage Measurement X   X
Post Enumeration Survey   X  

Mailout/Mailback and Update/Leave/Mailback

Two questionnaire delivery methodologies were used in the Dress rehearsal. The mailout/mailback methodology involved delivery by the United States Postal Service. There were four components of the mailout/mailback delivery: an advance letter, an initial questionnaire, a reminder card, and a "blanket" replacement questionnaire (mailed to all addresses). The update/leave/mailback methodology involved Census Bureau enumerators delivering the questionnaires at the same time they updated maps and the list of addresses. In addition to the delivery of questionnaires by Census enumerators, the U.S. Postal Service delivered an advance letter and a reminder card to all "Postal Patrons" within the update/leave area. Under both delivery methodologies, respondents were asked to mail back their questionnaires in provided envelopes.

Short and long form questionnaires were included in both delivery methodologies. Every household received either a short or a long form. The observed rates for the dress rehearsal sites varied since the sampling rate varied by size of place. Using the same sampling plan for the entire nation for Census 2000, we would expect about 17 percent of all households to receive a long form.

Nonresponse Followup - 100%

In Columbia, South Carolina and Menominee, Wisconsin a 100 percent followup for households not returning their Census questionnaires was used. This procedure sent enumerators to all addresses and/or locations that received a mailed questionnaire, or had a questionnaire delivered in person, and did not return it by a specified date. This followup operation continued until a response from the household was received, or proxy information was obtained.

Sample Nonresponse Followup

In Sacramento, California a sample nonresponse followup was used. Instead of following up all addresses that did not return a census form, enumerators followed up a sample of nonrespondents. The sample was designed so that each census tract reached a final completion rate of at least 90 percent.

For example, if the initial completion rate in a census tract, defined as:

# of Respondents
--------------------------------------------------- x 100
Total number of Addresses

was 60 percent, then a 3-in-4 systematic sample of nonrespondents was selected to reach the 90 percent completion target. If a census tract had at least an 85 percent initial completion rate, then the sampling rate was 1-in-3.

Followup continued for these sample-selected households until a response is received, or proxy information was obtained. Through statistical estimation techniques, responses for all of the other nonresponse households were derived from the sample responses. Additionally, all nonrespondent addresses that were added to the address list too late to be mailed a census form were also included in the nonresponse followup sample.

Integrated Coverage Measurement (ICM)

This operation is independent of the Dress rehearsal operation and was used in Sacramento, California and Menominee, Wisconsin. There are three phases to this operation: Housing Unit phase, ICM Interview phase, and Person Matching and Reconciliation phase. The Housing Unit phase compiled a list of housing units (within selected sample blocks) confirmed to be in existence on census day. This list was created independently of the Dress rehearsal, using a workforce that was independent of the one used for Dress rehearsal. Enumerators used this list to conduct the second phase. During the Interview phase, enumerators collect information about current residents and those who moved out of the sample block between census day and the time of the interview. This interview is done by personal visit or telephone. The Person Matching and Reconciliation phase involves matching persons enumerated in the ICM process with persons enumerated during the Dress rehearsal operations. Selected cases warranted additional interviews to reconcile differences in recorded data.

After completing all matching, estimates were developed of the number of people missed or duplicated during the Dress rehearsal operations by means of statistical methods. These ICM results were incorporated into the final Dress rehearsal enumeration to produce "one number" estimates of the population.

Post Enumeration Survey (PES)

This operation was independent of Dress rehearsal operations and was used in Columbia, South Carolina. Like the ICM, it was used to develop an estimate of the undercount from Dress rehearsal operations.

The field procedures used for PES were very similar to those used during the ICM. The difference between the two is that the PES estimates were not used to produce the final Dress rehearsal results.

Authors: J. Gregory Robinson, Kirsten West, and Arjun Adlakha (Population Division)
Created: May 26, 2000