PART 90—PROCEDURE FOR CHALLENGING POPULATION ESTIMATES Authority: 13 U.S.C. 4 and 181. Source: 88 FR 17705, Mar. 24, 2023, unless otherwise noted. § 90.1 Scope and applicability. Between decennial censuses, the Census Bureau annually prepares statistical estimates of the number of people residing in States and their governmental units. In general, these estimates are developed by updating the population counts produced in the most recent decennial census with demographic components of change data and/or other indicators of population change. These rules prescribe the administrative procedure available to governmental units to request a challenge to the most current of these estimates. § 90.2 Policy of the Census Bureau. It is the policy of the Census Bureau to provide the most accurate population estimates possible given the constraints of resources and available statistical techniques. It is also the policy of the Census Bureau, to the extent feasible, to provide governmental units the opportunity to seek a review of and provide additional data for these estimates and to present evidence relating to the accuracy of the estimates. § 90.3 Definitions. As used in this part (except where the context clearly indicates otherwise) the following definitions shall apply: (a) Census Bureau (b) Population Estimates Challenge (c) Director (d) Population estimate (e) A governmental unit (f) A non-functioning county or statistical equivalent [88 FR 17705, Mar. 24, 2023, as amended at 91 FR 2855, Jan. 23, 2026] § 90.4 [Reserved] § 90.5 Who may file a request for a challenge. A request for a challenge of a population estimate generated by the Census Bureau may be filed only by the chief executive officer or highest elected official of a governmental unit. In those instances where the FSCPE member agency represents a non-functioning county or statistical equivalent, the governor will serve as the chief executive officer or highest elected official. § 90.6 When a request for a challenge may be filed. (a) A request for a challenge to a population estimate may be filed any time up to 90 days after the release of the estimate by the Census Bureau. Publication by the Census Bureau on its website ( www.census.gov (b) The Census Bureau has the discretion to accept late requests. [88 FR 17705, Mar. 24, 2023, as amended at 91 FR 2855, Jan. 23, 2026] § 90.7 Where to file a request for a challenge. A request for a population estimate challenge must be prepared in writing by the governmental unit and filed with the Chief, Population Division, Census Bureau by sending the request via email to [email protected] census.gov § 90.8 Evidence required. (a) The governmental unit shall provide whatever evidence it has relevant to the request at the time of filing. The Census Bureau may request further evidence when necessary. The evidence submitted must be consistent with the criteria, standards, and regular processes the Census Bureau employs to generate the population estimate. Currently, the Census Bureau challenge process cannot accept estimates developed from methods different from those used by the Census Bureau. (b) For counties and statistical equivalents, the Census Bureau uses a cohort-component of change method to produce population estimates. Each year, the components of change are updated. These components include births, deaths, migration, and change in the group quarters population. The Census Bureau will consider a challenge based on additional information on one or more of the components of change or about the group quarters population in a locality. (c) For minor civil divisions and incorporated places, the Census Bureau uses a housing unit method to distribute a county population to places within its legal boundaries. The components in this method include housing units estimates, average household population per housing unit, and an estimate of the population in group quarters. The estimation formula was simplified to increase the accuracy of the estimates following the application of differential privacy as per the Census Bureau's new disclosure avoidance framework. As a result, the persons per household (PPH) and occupancy rate components were replaced with the average household population per housing unit. Additionally, the Census Bureau will consider a challenge based on data related to changes in an area's housing stock, such as data on demolitions, condemned units, uninhabitable units, building permits, or mobile home placements or other housing inventory-based data deemed comparable by the Census Bureau. The Census Bureau will also consider a challenge based on additional information about the group quarters population in a locality. (d) The Census Bureau will also provide a guide on its website as a reference for governmental units to use in developing their data as evidence to support a challenge to the population estimate. In addition, a governmental unit may address any additional questions by contacting the Census Bureau at 301-763-2461 or by sending emails to [email protected] census.gov [88 FR 17705, Mar. 24, 2023, as amended at 91 FR 2855, Jan. 23, 2026] § 90.9 Review of a request for a challenge. The Chief, Population Division, Census Bureau, or the Chief's designee shall review the evidence provided with the request for the population estimate challenge, shall work with the governmental unit to verify the data provided by the governmental unit, and evaluate the data to resolve the issues raised by the governmental unit. Thereafter, the Census Bureau shall respond in writing with a decision to accept or deny the challenge. In the event the Census Bureau finds that the population estimate should be updated, it will also post the revised estimate on the Census Bureau's website ( www.census.gov [91 FR 2855, Jan. 23, 2026]