The result will be "a census that is accurate, fair and cost-effective," Commerce Secretary William Daley told the Senate Governmental Affairs Committee on Tuesday.
The plan is to ensure that at least 90 percent of all households in each tract - an area of several square blocks - are counted via mailed-back questionnaire, telephone call or personal visit. That information can then be used to account for the remaining 10 percent.
In areas where at least 90 percent of the households respond to the initial mailing, Census workers will visit one in 10 of the remaining households. In areas with lower response rates a larger share of the missing will get personal visits, the bureau said. For example, if only 60 percent mail back the questionnaire, Census workers will call or visit three-quarters of the non-responding homes.
"Innovations planned for Census 2000 are all aimed at making it easy to be counted," said Census Director Martha Farnsworth Riche. "These run the gamut from a user-friendly questionnaire to multiple mailings to use of phone interviews to multiple language assistance."
Under the new system, once the initial response is in, workers will be assigned a list of houses that did not respond. The list will include enough households to bring the total up to 90 percent.
Earlier, the bureau had planned to have workers choose which houses to visit to bring their total to 90 percent.
The new plan will assign them to addresses selected for sampling, making the sampling statistically more fair and accurate, and completing it more quickly, officials said.
In addition, the bureau will select a sample of 750,000 households across the country to sample as a double-check on their numbers.
The idea of using statistical techniques to estimate a portion of the population has generated some controversy. Statisticians insist that sampling techniques have been refined enough to produce accurate figures, while opponents insist that the Constitution required an actual head count.
Under the Constitution, the Census must be taken every 10 years and the numbers are used to distribute seats in the House of Representatives and to calculate eligibility for federal aid programs.
Every census has generated controversy, starting with the first one in 1790 when President George Washington insisted that the number was too low.
Census officials admit that they cannot count everybody and that their totals are less accurate for minorities than for the general population.
The methods planned for use in 2000 will be tested in a census dress rehearsal next year in Sacramento, Calif., 11 counties in the Columbia, S.C. area, and on the Menominee Indian Reservation in Wisconsin. Census 2000 is expected to cost $3.9 billion - less than the estimated $4.8 billion it would have cost to duplicate the 1990 effort.
The 1990 cost of $2.5 billion was widely criticized, however, and Congress can be expected to raise questions about money again.