How Does the Census Process Actually Work?

In early March 2000, 98 million census forms -- both long and short forms -- went out in the mail to about 83 percent of the nation's residences. In addition, census enumerators personally delivered about 22 million additional forms to homes that lack street-name and house-number addresses, mostly in rural and remote areas. These represent about 17 percent of the nation's housing units. Hundreds of thousands of census takers and support personnel have been hired to account for the anticipated 118 million housing units and 275 million people across the United States.

The questionnaires were preceded by an advance letter sent a week or so earlier. This letter gave residents the option of asking for questionnaires in five languages besides English: Spanish, Tagalog, Korean, Chinese and Vietnamese. Later this month (March), the Census Bureau then sent a reminder card asking residents to mail back the form as soon as possible.

During March of a census year, the Census Bureau conducts special operations to count people with no fixed address or who live in dormitories, nursing homes, prisons, shelters, trailer parks, transient housing and other groups or non-standard housing.

After April 1, census workers spend a couple of months trying to locate and get information from households or families that failed to respond by mail. If your questionnaire is incomplete, a census employee must contact you to obtain the missing information. Then these answers are combined with those on your questionnaire. It is these combined numbers --not your individual answers -- that are published.

As census methodology has become more sophisticated, researchers have begun to learn more about who responds and who doesn't. For example, the overall non-response rate in 1990 was 25.3 percent. Researchers say response -- or lack of response -- to the mailed 1990 Census questionnaires was highly correlated with race and length of time at a residence. Researchers also said that mail response to the 1990 Census was strongly related to family composition (the number of parents in the home, the age of the single parent, etc.).