Demographia

Early Census Results: Sampling Misses by a Mile

On December 28, 2000, the United States Census Bureau released its count of the nation's population from the 2000 census (as of April 1). At 281,421,906 the reported population is well above the Census Bureau's April 1, 2000 estimate of 274,520,000. The actual census count was nearly seven million higher than the Census Bureau's estimate, an amount nearly equal to the population of the city of New York.

While the Census Bureau had estimated an increase in US population of 25.7 million, the actual increase was 27 percent higher, at 32.7 million. By comparison, in 1990, the Census Bureau estimate was within 1.5 million of the enumeration.

The amount by which the Census Bureau missed the mark was much greater in some areas (complete results shown in the attached table).

  • The District of Columbia was estimated to have lost more than 90,000 residents since 1990.(1) In fact, the loss was much smaller, at 35,000.

  • The state of New York was estimated to have increased approximately 200,000. The actual increase was nearly one million. The Census Bureau's nearly 800,000 error is equal to the population of the states second through fourth largest cities (Buffalo, Rochester and Yonkers).

  • Pennsylvania's actual increase was more than three times the Census estimate.

  • States that were estimated to have lost population were found instead to have gained. For example, Connecticut's estimated 9,000 loss was instead a nearly 120,000 gain.

  • The Florida error of nearly 700,000 is more than the combined population of Miami and Tampa combined.

    Between censuses, the Census Bureau uses a sophisticated sampling technique to produce annual estimates of state population and monthly estimates of the national total. If such methods had advanced to the point of reliability, the rather substantial errors apparent in the 2000 estimates would not have occurred.

    The issue of the Census Bureau's erroneous projections is important in light of proposals to use statistical analysis and sampling to adjust the census counts. Under a US Supreme Court decision, such adjustment would be permitted for all uses except the apportionment of Congressional seats between the states. This means, for example, that the drawing of Congressional district borders within a state could be based upon adjusted figures. There are two fundamental problems with statistical adjustment of the Census figures. First; the errors described above are evidence that the state of the art is not sufficiently advanced, and particularly at the Census Bureau. Second; statistical adjustment introduces the potential of political manipulation of the Census.

    The experience of another US government sampling program earlier in 2000 is instructive. The Department of Agriculture's National Resources Inventory reported large expansions of urbanization and losses of farmland in a number of states, most notably Pennsylvania, Texas, Virginia and Georgia. Administration officials, eager to make points to support their hysteria about urban sprawl, rushed to publicize the results. There was only one problem --- the data, which was based upon statistical sampling was wrong. The author and Dr. Ronald D. Utt had previously notified the Department of Agriculture of fundamental discrepancies between the statistically sampled NRI and the Agricultural Census for the same year. After some press attention had been obtained, the Department of Agriculture withdrew the numbers announcing a "computer program error."(2) There may have indeed been a computer program error. But it is not inconceivable that bureaucrats might have been rushed into premature press releases by officials interested in advancing a particular political agenda.

    Finally, the nation witnessed first hand the problems with statistical sampling on election night, when premature and erroneous projections were made and withdrawn. The last thing the nation needs is such a fiasco applied to its decennial census.

    Change in Resident Population from 1990
    State or District Estimate Count Error
    Alabama 352,874 406,513 53,639
    Alaska 74,855 76,889 2,034
    Arizona 1,212,249 1,465,404 253,155
    Arkansas 215,168 322,675 107,507
    California 3,643,596 4,111,627 468,031
    Colorado 826,744 1,006,867 180,123
    Connecticut (8,666) 118,449 127,115
    Delaware 94,202 117,432 23,230
    Florida 2,349,993 3,044,452 694,459
    Georgia 1,419,562 1,708,237 288,675
    Hawaii 82,613 103,308 20,695
    Idaho 266,019 287,204 21,185
    Illinois 744,408 988,691 244,283
    Indiana 426,531 536,326 109,795
    Iowa 97,527 149,569 52,042
    Kansas 188,749 210,844 22,095
    Kentucky 294,905 356,473 61,568
    Louisiana 160,395 249,003 88,608
    Maine 25,958 46,995 21,037
    Maryland 418,137 515,018 96,881
    Massachusetts 165,821 332,672 166,851
    Michigan 606,495 643,147 36,652
    Minnesota 429,793 544,380 114,587
    Mississippi 209,193 271,442 62,249
    Missouri 375,472 478,138 102,666
    Montana 90,015 103,130 13,115
    Nebraska 93,343 132,878 39,535
    Nevada 666,629 796,424 129,795
    New Hampshire 98,490 126,534 28,044
    New Jersey 439,784 684,162 244,378
    New Mexico 242,700 303,977 61,277
    New York 205,375 986,002 780,627
    North Carolina 1,104,158 1,420,676 316,518
    North Dakota (6,160) 3,400 9,560
    Ohio 432,512 506,025 73,513
    Oklahoma 227,042 305,069 78,027
    Oregon 512,307 579,078 66,771
    Pennsylvania 109,939 399,411 289,472
    Rhode Island (14,619) 44,855 59,474
    South Carolina 429,536 525,309 95,773
    South Dakota 39,514 58,840 19,326
    Tennessee 653,353 812,098 158,745
    Texas 3,308,825 3,865,310 556,485
    Utah 441,832 510,319 68,487
    Vermont 32,992 46,069 13,077
    Virginia 737,667 891,157 153,490
    Washington 962,930 1,027,429 64,499
    West Virginia 12,800 14,867 2,067
    Wisconsin 383,787 471,906 88,119
    Wyoming 27,722 40,194 12,472
    DC (94,937) (34,841) 60,096
    United States 25,810,127 32,712,033 6,901,906


    1 The Census Bureau has not issued 2000 estimates for states and the District of Columbia. This paper uses the 1999 estimates and produces a 2000 estimate based upon the rate of Census Bureau estimated change from 1990 to 1999, scaled to the national estimate.

    2 Heritage Foundation Backgrounder #1368

    (c) 2000 www.demographia.com --- Wendell Cox Consultancy --- Permission granted to use with attribution.
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