METHODOLOGY for ESTIMATES of STATE POPULATION by AGE and SEX Source: U.S. Bureau of the Census Release date: June, 1999 Extracted from P25-1127 The state age-sex estimates are produced with a state estimates model that is a version of Component Method II. Estimates are produced for each single year of age by sex up to age 65. In this method each age follows the standard demographic formula of P1 = P0 + B - D + M: where P1 is the population on the estimate date; P0 is the population on the census date; B and D are the births and deaths occurring during the estimate period, and M is the net migration (including international net migration) occurring during the estimate period. This is a cumulative method, where the estimate period is from the date of the last census to the estimate date. The steps used in estimating single years of age (0 to 64) for the civilian population are summarized below: 1. The resident cohort population by single year of age is developed by carrying forward the April 1, 1990 census count (for each age) to the July 1 estimate date; 2. Births entering each cohort for the period between April 1, 1990 and the July 1 estimate date are added where appropriate; 3. An estimate of the Armed Forces cohort population for each age 17-64 on the estimate date, is subtracted from the resident cohort population to create the civilian cohort population; 4. An estimate of the net civilian migration for 1990 to the estimate date is added; 5. An estimate of the net change in civilian population entering the Armed Forces population during the estimate period is added. The result of these five steps is unadjusted civilian age estimates, but without sex detail. Sex detail originates from the following steps: (1) The 1990 census proportion of male civilian population is calculated for each year of age by State; (2) national sex ratios by single year of age are calculated for both the 1990 census civilian population and for each estimate year; (3) the change in the national sex ratios between the estimate year and the census base year are used to update the 1990 State ratios; and (4) these are applied to the State single- year civilian population estimates for both sexes to obtain civilian sex detail by age. Final steps in the component method for age are to: (1) adjust each age-sex cell (0 to 64) to an independent national civilian population estimate; (2) further adjust each age-sex cell within a State to the civilian state population total; (3) Add estimates of Armed Forces by age and sex to the civilian population to produce resident population. The vital statistics used in the age estimates are from the same sources used in the Federal Tax Returns Method. The net migration component revolves around elementary school enrollment and school-age migration. It is developed in two age segments: (1) State school-age net migration for the estimate period is used to formulate an amount of net migration for each age under age 17; and (2) Each state's school-age migration rate is converted to net migration rates for single years 17 through 64, then applied to a base (cohort for that age minus 1/2 the deaths to the cohort) in order to derive net migration amounts. The Armed Forces data used in this method are obtained from the Departments of Defense and Transportation. All military persons are assumed to be between the ages of 17 and 64. State Armed Forces data are not provided by age or sex. National level data are used to assign age-sex detail to the States. The group quarters data are updated on an annual basis.