Census

The United States Constitution requires a census or "actual enumeration" of the nation's population every 10 years. Census figures are used to divide House seats among the states, draw voting boundaries for all elected offices, and allocate federal funds for everything from roads to law enforcement grants each year. The census is conducted by mail, with workers fanning out to find people after about two-thirds of Americans return their forms.  Sampling is used after 90 percent of the forms are returned to census-takers. The characteristics of the remaining 10 percent are determined through a statistical formula based on the forms that have already been returned.

Many people might be surprised to learn that veteran researchers would choose a sample over a census for purposes of accuracy.  The census involves a large number of interviewers, which in turn introduces a greater potential for nonsampling error. Statistical sampling, simply put, is a very educated way to guess the size of the U.S. population.  Demographic experts say that every census since the first one in 1790 has been inaccurate because it is virtually impossible to count every American. The 1990 census was the first one in 50 years to be less accurate than its predecessor.  It is believed to have missed 8 million people and counted 4 million others twice.  The Census Bureau knows this because it uses samples to infer the accuracy of the census!  The Census Bureau proposed sampling as a way to correct problems from the 1990 census.  Furthermore, the National Academy of Sciences endorsed it as a means to obtain a more accurate census in 2000.

On January 25, 1999 the Supreme Court said that the 2000 census couldn’t be adjusted to more accurately reflect minorities. Justice Sandra Day O'Connor, writing for the court majority, said that the census law "directly prohibits the use of sampling in the determination of population for purposes of apportionment." Chief Justice William Rehnquist and Justices Antonin Scalia, Anthony Kennedy and Clarence Thomas joined Justice O'Connor in the majority opinion.  The court ruling left open the possibility that adjustments, known as sampling, could be made for purposes of distributing federal funds to the states and for drawing federal, state and local legislative districts.

In writing the dissent, Justice John Paul Stevens said the census law "gives the Secretary of Commerce unqualified authority to use sampling procedures when taking the decennial census."  Justice Stevens also said the law "does not command the secretary" to use sampling, but "neither does it prohibit" those statistical methods.  Justices David Souter, Ruth Bader Ginsburg and Stephen Breyer also dissented.

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Copyright © 1999 by Gemmy Allen, all rights reserved.