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The Decennial Census and Congressional Apportionment

Published onJan 31, 2020
The Decennial Census and Congressional Apportionment
key-enterThis Pub is a Commentary on

Teresa Sullivan’s (2020) article “Coming to Our Census” is an extremely important presentation and discussion of, among other things, the role of the decennial census and its accompanying data in maintaining our country’s democracy. I agree with the points she has raised and discussed in her article. My comments will more so build upon and focus and elaborate on a few parts of her article than it will present remarks that would provoke controversy or criticism. The bulk of my discussion focuses on the census and congressional apportionment, and extends Sullivan’s article in her sections, “Representation and Allocation,” “The Census is Constitutionally Required,” and “The Citizenship Question.”

Sullivan correctly notes that the decennial census is mandated in the U.S. Constitution. Allow me to further elaborate on this most important point. The primary purpose of the decennial census is to provide population counts for the states that are then used in apportioning the U.S. House of Representatives. The requirement for a decennial census was written in 1787 into Article 1, Section 2, of the U.S. Constitution as follows: “Representatives and direct taxes shall be apportioned among the several states which may be included within this Union according to their respective numbers.... The actual enumeration shall be made within three years after the first meeting of the Congress of the United States, and within every subsequent term of ten years in such manner as they shall by law direct.”

Although the Constitution requires that apportionment be based on the size of a state’s population, it does not specify the persons that should be included in the apportionment population. This omission has resulted in contentious debates over the years with respect to whether noncitizen U.S. residents and undocumented U.S. residents should be included in the apportionment population, that is, the counts of persons in the states to be used to apportion the House.

If the goal is to ensure an equal voice among voters, or electoral equality, then the apportionment population should be limited only to citizens eligible to vote. This, however, results in many states having large portions of their populations unrepresented, including children, legal and undocumented immigrants, and disenfranchised felons (Cowan, 2015; Tienda, 2002). On the other hand, if the goal is representational equality, then each elected official should represent an equal number of people, regardless of whether those individuals are eligible to vote; all that matters is that they reside in the state (Baumle & Poston, 2019).

Currently, the apportionment population of a state is defined as the total resident population of the state plus the “overseas population” from that state, that is, those U.S. government employees and members of the military and their dependents serving overseas, who claim the state as their “state of record” (Baumle & Poston, 2019, p.385).

The Constitution is also silent regarding the method to be used in apportioning the House. The Method of Equal Proportions, that I will mention below, is the apportionment method that will be used in the 2020 apportionment. It was first used in the 1940 apportionment and has been used in every apportionment since. Prior to 1940, there had been an abundance of apportionment procedures introduced, considered, and used since the first apportionment following the 1790 census (Poston, 1997).

When apportioning the House, the main objective is to assign equitably the 435 seats to the 50 states; the District of Columbia is not included in the apportionment and thus does not receive representation in the House. There are several constraints: 1) the total number of House seats must equal 435; 2) partial seats cannot be assigned to states, nor can representatives be given fractional votes; 3) representatives may not be shared by two or more states; and 4) every state must be assigned at least one seat in the House (Baumle & Poston, 2019).

The first 50 seats are automatically assigned, one per state. The Method of Equal Proportions is then used to assign the remaining 385 seats. It identifies which states should receive second seats, which states should receive third seats, and so forth. Although, as I have noted, the Constitution does not dictate how the apportionment should be carried out, the underlying assumption is ‘one man, one vote.’ That is, no one person should have more of a voice than another person. Representatives are assigned to states in proportion to their populations. But as Balinski and Young (1982, p. 1) have argued, the notion of proportionality is not enough by itself to “solve the problem of apportionment” because it does not address what is to be done with fractions (also see Anderson, 2015).

The Method of Equal Proportions is used to solve this problem of remainders. It was proposed in 1911 by Joseph A. Hill, a U.S. Census Bureau statistician, and supported by Professor Edward V. Huntington of Harvard University (Huntington, 1920). Equal Proportions is a divisor method that first develops a target ratio of population to representatives that is based on data for the nation, excluding the District of Columbia, that are then applied to each state with regard to its possible second, third, and higher order seats. It endeavors to ensure that “the difference between the representation of any two states is the smallest possible when measured both by the relative difference in the average population per district, and also by the relative difference in the individual share in a representative” (Schmeckebier, 1941, p. 22). It gives to a state another representative “when its [apportionment] population, divided by the geometric mean of its present assignment of representatives and of its next higher assignment, is greater than the [apportionment] population of any other state divided by the geometric mean of the assignment to such other state and its next higher assignment” (Schmeckebier, 1941, p. 22).

My student, Amanda Baumle—now a professor of sociology at the University of Houston—and I, have projected to 2020 the apportionment populations of the 50 states and have then used the Method of Equal Proportions to distribute among the states the remaining 385 House seats (Baumle & Poston, 2019). Remember that every one of the 50 states automatically receives one seat.

If our 2020 projections are correct, there will be in 2020 a net change of nine seats in the U.S. House. We project that Texas will gain three seats in 2020, Florida will gain two seats, and Arizona, Colorado, North Carolina, and Oregon will each gain one. Nine states will each lose one seat in the 2020 apportionment, namely, Alabama, Illinois, Michigan, Minnesota, New York, Ohio, Pennsylvania, Rhode Island, and West Virginia. The state with the largest number of House seats in 2010 was California with 53 seats; our projections indicate that California will neither gain nor lose seats in 2020. California has had 53 seats since the 2000 apportionment. However, analyses conducted by the Election Data Services (EDS) using 2019 state estimates produced by the U.S. Census Bureau are slightly different from those of Baumle and me which used data for 2016. Their seat assignments also indicate that Montana will gain a seat and California will lose a seat; otherwise their results are the same as those of Baumle and me.

Sullivan (2020) also writes about discussions in the past two years regarding including a ‘citizenship question’ on the 2020 census. The courts ruled against this action, and Sullivan’s article entertains many important aspects and implications of this decision. It turns out that most Republicans favored including the citizenship question, and most Democrats argued against including the question.

Sullivan correctly notes that had a citizenship question been included on the census, many people, especially undocumented persons, would likely have been afraid to answer the question and may not have responded to the census and thus would not have been counted as residents of their states. What effect would this have on the distribution of seats in the House?

Baumle and I thus performed two more 2020 apportionments of the House; in one scenario we excluded all of the nearly 10-plus million undocumented persons from their states of residence, and in a second scenario we excluded 50% of the undocumented residents (Baumle & Poston, 2019). We showed that if all the nearly 10-plus million undocumented immigrants in the United States did not respond to the census and were thus not counted, four states would lose one of their projected new seats: Arizona, California, Florida, and Texas. Meanwhile, Alabama, Minnesota, Montana, and Ohio would each gain one. If 50% of the undocumented immigrants did not fill out the census questionnaire, and were thus not counted, then Arizona, California, and Texas would lose a House seat, and Alabama, Minnesota, and Montana would gain one.

The big states that would have lost the most if a citizenship question was on the 2020 census are Texas, Arizona, and Florida—all states that voted for President Trump in 2016. In addition to also losing several billion dollars in federal funding every year, these heavily Republican states would have lost seats and political power in the U.S. House of Representatives. It is interesting to note that Republicans should be pleased that the president threw in the towel with the citizenship question. They are politically much better off than had the question been included (Poston & May, 2019).

Sullivan (2020) notes that “the Census is a large, complex undertaking, requiring huge expenditures of time and money and vast efforts to tabulate and analyze.” The data produced by the decennial census in many different ways aid in maintaining our democracy. Sullivan draws out many important features and implications of this relationship. In my discussion I have focused only on issues related to congressional apportionment and its political, social, and demographic implications.

Disclosure Statement

Dudley L. Poston, Jr., has no financial or non-financial disclosures to share for this article.


Anderson, M. J. (2015). The American census: A social history (2nd ed.). New Haven, CT: Yale University Press.

Balinski, M. L., & Young, H. P. (1982). Fair representation: Meeting the ideal of one man, one vote. New Haven, CT: Yale University Press.

Baumle, A. K., & Poston, D. L. Jr. (2019). Apportionment of the U.S. House of Representatives in 2020: Alternative immigration-based scenarios. Population and Development Review, 45(2), 379–400.

Cowan, S. K. (2015). Periodic discordance between vote equality and representational equality in the United States. Sociological Science, 2, 442–453.

Election Data Services. (2019). Montana gains California’s seat with new 2019 census estimates; but Alabama & Ohio to also lose by 2020. content/uploads/2019/12/NR_Appor19wTablesMaps.pdf?ftag=YHF4eb9d17

Huntington, E. V. (1920). A new method of apportionment of representatives. Quarterly Publication of the American Statistical Association, 17, 859–870.

Poston, D. L., Jr. (1997). The U.S. census and congressional apportionment. Society, 34, 36–44.

Poston, D. L., Jr., & May. J. F. (2019, July 24). Republicans gained by dropping citizenship question. The Bryan Eagle, A4.

Schmeckebier, L. F. (1941). Congressional apportionment. Washington, DC: Brookings Institution.

Sullivan, T. A. (2020). Coming to our census: How social statistics underpin our democracy (and republic). Harvard Data Science Review, 2(1).

Tienda, M. (2002). Demography and the social contract. Demography, 39(4), 587–616.

©2020 Dudley L. Poston, Jr. This article is licensed under a Creative Commons Attribution (CC BY 4.0) International license, except where otherwise indicated with respect to particular material included in the article.

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