This report describes the methodology used to prepare experimental estimates of the population by age and sex for all counties in the United States on July 1, 1975. For the first time, census data on gross outmigration and inmigration were used in developing age estimates for counties. Also, revised techniques in the treatment of military and college population were introduced.
The text discusses the general methodology used; preparation of migration data and birth cohort migration; preliminary approximation of the 1975 population; adjustments for consistency with national, State, and county estimates; and use of Medicare data for estimating the population aged 65 years and over. Eight text tables, illustrating and supplementing the text data are included.
Data are provided on the collapse procedure for smoothing migrant age distributions; a list of counties adjusted for military, college, and institutional population; major adjustments to the 1965 to 1970 migrant data; and definitions of technical terms used in the report.
Census statistics date back to 1790 and reflect the growth and change of the United States. Past census reports contain some terms that today’s readers may consider obsolete and inappropriate. As part of our goal to be open and transparent with the public, we are improving access to all Census Bureau original publications and statistics, which serve as a guide to the nation's history.