This report provides an overview of selected issues regarding census data that have arisen during recent decennial censuses, including use of sampling or other estimation techniques and counting U.S. citizens residing abroad. With regard to intrastate redistricting, all 50 states, the District of Columbia, and Puerto Rico currently receive census data for reapportionment and redistricting via the P.L. 94-171 census program. Adjustments to Census Data

Federal court findings that states are not required to use federal census data for redistricting but must use the best data available has raised questions over whether the Census Bureau must provide states with adjusted census data in addition to census apportionment data. The Ninth Circuit found, however, that the Secretary of Commerce had no affirmative duty under the Census Clause of the Federal Constitution (Art. §195 to adjust the official 2000 decennial census figures for intrastate redistricting purposes. If the Secretary of Commerce transmits an official adjusted data set, that data arguably could be considered official federal decennial census data even if it is not the data used to apportion the House of Representatives. The Court held that hot-deck imputation does not violate the Census Clause or the 13 U.S.C. Counting of Overseas Citizens

In November 2001, the U.S. Supreme Court affirmed a federal district court opinion upholding the Secretary of Commerce's decision to not include expatriate U.S. citizens, other than U.S. military and civilian federal government personnel, in the 2000 census data for reapportionment of the House of Representatives. 868 ) have been introduced in the 112 th Congress to mandate the inclusion of all expatriate U.S. citizens in the decennial census in accordance with specific guidelines but none have been enacted legislation yet.
This report provides an overview of selected issues regarding census data that have arisen during recent decennial censuses, including use of sampling or other estimation techniques and counting U.S. citizens residing abroad. The Constitution requires that state representation in the House of Representatives be based on a population census conducted at least once every 10 years. The Constitution does not expressly require use of official federal decennial census data for intrastate redistricting, but courts have found that states must use the best data available, which may or may not be official census data. Currently, all 50 states, the District of Columbia, and Puerto Rico receive census data for reapportionment and redistricting via the census program conducted pursuant to P.L. 94-171.
Under the Constitution and census statutes, the federal government has broad authority over how the census is conducted. The Supreme Court has found that federal law bars using sampling data to adjust the decennial census for House of Representatives reapportionment but that hot-deck imputation, an estimation technique, is permissible. Adjusting census data for other purposes, such as intrastate redistricting, is also not prohibited. In addition, the Secretary of Commerce has authority over whether it is feasible to release adjusted data for intrastate redistricting purposes.
The Supreme Court has held that the Secretary of Commerce has discretion whether to include overseas federal personnel in the apportionment census. It has also found that the Secretary of Commerce can include U.S. military and civilian federal government overseas employees in the apportionment census while excluding other expatriate U.S. citizens. Because Congress has authority to legislate census methodology with regard to treatment of expatriates, several bills have been introduced in the 112th Congress addressing the inclusion of expatriates and categories of expatriates.