|The United States Constitution mandates that the census be taken at least once every 10 years, and that the number of members of the House of Representatives from each state be determined accordingly. In addition, Census Bureau statistics are used for apportioning Federal funding for many social and economic programs. But there is not a federal census legislation (nor for federal voting).|
The first U.S. Census was taken in 1790 by the local U.S. Marshals. Census-takers went door-to-door and recorded the number of people in each household, and the name of the head of the household. Slaves were counted, but for apportionment purposes each counted as only three-fifths of a citizen. American Indians being neither taxed nor considered during apportionment, were not counted. The first census counted 3.9 million people, less than half the population of New York City in 2000. The 2000 census counted over 281 million people.
In 1902, a Public Law established the Census Bureau as a permanent Federal agency. In recent times, there were two forms of questionnaire – long and short. Currently, the plan is to replace the Long Form and its additional questions about items such as daily commute times, housing unit factors, etc. with the American Community Survey (ACS), prior to the 2010 census. Computer algorithms (based on complex sampling rules) determined which form was mailed to a given household (in practice, of those households whose locations are on the Census Master Address List), one in six receiving the long form. This was supplemented by census workers going door-to-door to talk to people who failed to return the forms. In addition to a simple count of residents, the Census Bureau collects a variety of statistics, on topics ranging from ethnicity to the presence of indoor plumbing. While some critics claim that census questions are an invasion of privacy, the data collected by every question is either required to enforce some federal law (such as the Voting Rights Act) or is required to administer some federal program. Congress gives approval to every question asked on the Census.
Despite a massive effort, the Census Bureau has never been able to count every individual, leading to controversy about whether to use statistical methods to supplement the numbers for some purposes, as well as arguments over how to improve the actual head count. The Supreme Court has ruled that only an actual head count can be used to apportion Congressional seats; however, cities and minority representatives have complained that urban residents and minorities are undercounted. In several cases, the Census Bureau will recount an area with disputed figures, provided the local government pays for the time and effort. The State of Utah protested the figures of the 2000 decennial census because it stood to gain a seat in the House of Representatives, but North Carolina gained it instead. Had the Census Bureau been able to count the numbers of Utahns living overseas, including many Mormon missionaries, Utah would have gained the seat.