The racial categories are officially described as follows:¹
The categories represent a social-political construct designed for collecting data on the race and ethnicity of broad population groups in this country, and are not anthropologically or scientifically based.
Furthermore, the race categories include both racial and national-origin groups.
Racial classification in the 2000 census was based solely on self-identification and, for the first time, did not pre-suppose disjointness:
The question on race asked respondents to report the race or races they considered themselves to be. Both questions are based on self-identification.
Nearly seven million Americans identified themselves as members of more than one race in the 2000 census.
For the 2000 census the Census Bureau considers race to be separate from Hispanic origin.
Because of changes to definitions, the Census Bureau issued the following warning:
The question on race for Census 2000 was different from the one for the 1990 census in several ways. Most significantly, respondents were given the option of selecting one or more race categories to indicate their racial identities. Because of these changes, the Census 2000 data on race are not directly comparable with data from the 1990 census or earlier censuses. Caution must be used when interpreting changes in the racial composition of the U.S. population over time.
The following definitions apply to the 2000 census only.
Black or African American refers to people having origins in any of the Black racial groups of Africa. It includes people who indicated their race or races as "Black, African Am., or Negro", or wrote in entries such as African American, Afro American, Nigerian, or West Indian.
American Indian and Alaskan Native refer to people having origins in any of the original peoples of North and South America (including Central America), and who maintain tribal affiliation or community attachment. It includes people who indicated their race or races by marking this category or writing in their principal or enrolled tribe, such as Cherokee, Chippewa, or Navajo.
Native Hawaiian and Other Pacific Islander refers to people having origins in any of the original peoples of Hawaii, Guam, Samoa, or other Pacific Islands. It includes people who indicated their race or races as "Native Hawaiian", "Guamanian or Chamorro", "Samoan", or "Other Pacific Islander", or wrote in entries such as Tahitian, Mariana Islander, or Chuukese . (See also: American Pacific Islander )