The United States Census of 2000 could cause federal funding for poor Detroit students to be cut, according to two advocacy groups.

The Children's Defense Fund (CDF) and the Council of Great City Schools (CGCS) said that billions of dollars in federal aid for Detroit schools will be lost if the 2000 census shows that Detroit's population has dropped under one million, the level at which cities are eligible for additional federal dollars. The census is a constitutionally mandated enumeration of citizens conducted every 10 years by the U. S. Census Bureau.

Detroit Mayor Dennis Archer and other city officials are challenging the way the census counts citizens due to claims that the 1990 census failed to account for as much as 62 percent of Detroit residents under age 18. The 1990 census placed Detroit's population at 1,027,974.

CDF estimates that the 1990 data did not credit Detroit for nearly 17,500 additional children and has concerns that the methods used to count citizens could also shortchange Detroit in 2000.

Michael Casserly, director of CGCS, estimates that every child not counted in the census means about $650 less for Detroit in federal resources per student or the equivalent of $16,250 for every classroom of 25 students. Much of the federal money is spent on special education programs that do not receive state funding.

Archer and others are calling for the Census Bureau to adopt a statistical technique known as "sampling" to count urban residents who might otherwise be missed by the census takers. Sampling, however, was ruled unconstitutional by the U. S. Supreme Court in January 1999. The court's 5-4 ruling requires that a traditional head count be used to determine the number of people in the United States.

The outcome of the 2000 census may also cause Detroit to lose its ability to impose a city income tax. Michigan law stipulates that only cities with one million or more residents may levy an income tax.

Detroit's income tax is 3 percent for residents, 2 percent for corporations, and 1.5 percent for nonresidents who work in the city. The city's overall municipal tax burden is more than six times higher than average for Michigan municipalities.