2001 methodology

2001 Methodology: Resident Population Estimates of the United States

Resident Population Universe Definition

Estimates of the United States resident population include persons resident in the 50 States and the District of Columbia. They exclude residents of the Commonwealth of Puerto Rico, and residents of the outlying areas under United States sovereignty or jurisdiction (principally American Samoa, Guam, Virgin Islands of the United States, and the Commonwealth of the Northern Mariana Islands). The definition of residence conforms to the criterion used in the Census 2000 which defines a resident of a specified area as a person "usually resident" in that area. Estimates of resident population exclude the United States Armed Forces overseas, as well as civilian United States citizens whose usual place of residence is outside the United States.

Postcensal Estimation of Resident Population

Estimates of the United States population were derived quarterly by updating the resident population enumerated in Census 2000 through the components of population change. The following formula was applied to update each group:

1. 2000 enumeration of U.S. resident population,
2. + births to U.S. resident women,
3. - deaths to U.S. residents,
4. + net international migration,
5. + net movement of U.S. Armed Forces and civilian citizens to the United States.

1. The 2000 enumerated resident population comes from the April 1, 2000 Decennial Census.

2. Registered births to United States resident women are estimated from data supplied by the National Center for Health Statistics. The primary source for this birth data can be found in the National Center for Health Statistics (NCHS), Monthly Vital Statistics Report, Volume 49, Number 1, "Births: Final Data for 1999," and similar publications of NCHS.
3. Registered deaths to United States residents are also estimated from data supplied by the National Center for Health Statistics. The primary source for this death data can be found in the National Center for Health Statistics National Vital Statistics Report, Volume 49, Number 8, "Deaths: Final Data for 1999," and similar NCHS publications.
4. The net international migration component in the population estimates includes: (1) legal immigration to the United States, (2) emigration of foreign born and native people from the United States, (3) net movement between the United States and Puerto Rico, (4) estimates of temporary migrants, and (5) estimates of net residual foreign-born population, which include unauthorized migration. The estimate of legal immigration is developed from data supplied by the Immigration and Naturalization Service.

   The remaining subcomponents of net international migration are consistent with the estimates for 1990 and 2000 developed for the Demographic Analysis and Population Estimates (DAPE) project (See Deardorff and Blumerman, 2001 "Evaluating Components of International Migration: Estimates of the Foreign-Born Population by Migrant Status in 2000", Population Division Working Paper Series No. 58). The net residual foreign-born population includes unauthorized population and people in "quasi-legal" status who are waiting action on their legal migration requests, among others (See Costanzo, et al. 2002. "Evaluating Components of International Migration: The Residual Foreign-Born", Population Division Working Paper Series No. 61.) For the April 2000 to July 2001 period, the levels of the various components are:

   Net International Migration by Component: April 2000 to July 2001
   Legal immigration	969,007
   Emigration of foreign born population	238,020
   Emigration of native born population	22,515
   Net movement between the US and Puerto Rico	13,915
   Net change in the residual foreign-born population (including unauthorized migration)	617,440
   Net change in temporary migrants	0
   Total Net International Migration	1,339,827

   (Note: The number of temporary migrants, estimated at 781,507 for the census date 2000, is assumed to remain constant throughout the estimate period).

5. The movement of federal employees (both military and civilian) and their dependents into and out of the United States consists mainly of movement of the active duty Armed Forces and their dependents. Armed Forces overseas strength statistics are supplied by the five branches of the Armed Forces in the Departments of Defense (Army, Navy, Marines, and Air Force) and Transportation (Coast Guard).

Monthly Population Estimates

The monthly estimates are produced through interpolation from the quarterly estimates. The third and fourth quarters of 2001 and all of 2002 are derived through extrapolation of current trends in the components of population change.

Notes

Population estimates are subject to revision, as revised input data become available. These revisions normally occur once a year in the spring. The most recent estimates shown here will be subject to monthly update.