The ACS is part of the 2010 Decennial Census Program and is an alternative method for collecting the long-form sample data collected in the last five censuses. The long-form sample historically collected detailed population and housing characteristics once a decade through questions asked of a sample of the population.1
Beginning in 2005, the ACS collects this detailed information on an ongoing basis, thereby providing more accurate and timely data than was possible previously. Starting in 2010, the decennial census will include only a short form that collects basic information for a total count of the nation's population.2
Historically, the content of the long form was constrained by including only the questions for which:
- There was a current federal law calling for the use of decennial census data for a particular federal program (mandatory).
- A federal law (or implementing regulation) clearly required the use of specific data, and the decennial census was the historical or only source; or the data are needed for case law requirements imposed by the U.S. federal court system (required).
- The data were necessary for Census Bureau operational needs and there was no explicit requirement for the use of the data as explained for mandatory or required purposes (programmatic).
Constraining the content of the ACS was, and still is, critical due to the mandatory reporting requirement and respondent burden. To do this, the Census Bureau works closely with the OMB and the Interagency Committee for the ACS, co-chaired by the OMB and the Census Bureau. This committee was established in July 2000, and includes representatives from more than 30 federal departments and agencies that use decennial census data. Working from the Census 2000 longform justification, the initial focus of the committee was to verify and confirm legislative justifications for every 2003 ACS question. The agencies were asked to examine each question and provide the Census Bureau with justification(s) by subject matter, the legal authority for the use, the lowest geographic level required, the variables essential for cross-tabulation, and the frequency with which the data are needed. They were asked to cite the text of statutes and other legislative documentation, and to classify their uses of the ACS questions as "mandatory," "required," or "programmatic," consistent with the constraints of the traditional long form.
In the summer of 2002, the U.S. Department of Commerce General Counsel's Office asked each federal agency's General Counsel to examine the justifications submitted for its agency and, if necessary, to revise the information so that the agency would be requesting only the most current material necessary to accomplish the statutory departmental missions in relation to census data. This step ensured that the highest-ranking legal officer in each agency validated its stated program requirements and data needs.
Only questions on those subjects classified as either "mandatory" or "required" were asked on the 2003 ACS questionnaire, along with questions on two programmatic subjects (fertility and seasonal residence). The end result of this review was a 2003 ACS questionnaire with content almost identical to the Census 2000 long form. In 2002, the ACS questionnaire was approved for 3 years by the OMB in its role of implementing the 1995 Paperwork Reduction Act.
Sampling began in the 1940 census when a few additional questions were asked of a small sample of people. A separate long-form questionnaire was not implemented until 1960.
In addition to counting each person in every household, the basic information planned for the Census 2010 short form will include a very select set of key demographic characteristics needed for voting rights and other legislative requirements. Currently, the plan is to ask for data on tenure at residence, sex, age, relationship, Hispanic origin, and race.