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Scientific Data Documentation

Intercensal Population Estimates, Bureau of the Census, 1980-1989

y8089.burcen

Annoucement: January/February 1993
Abstract
Methodology
Record Layout

 ANNOUNCEMENT: INTERCENSAL USAGE NOTES/NEWS


 Source:  APDU Newsletter
          Volume 17, No. 1
          January/February 1993


 Director Announces No Adjustment ofIntercensal Estimates

     Barbara Bryant, Director of the Bureau of the Census, announced on
 December 29 that the intercensal population estimates produced annually
 by the Bureau will not be adjusted to correct for the estimated 1.6%
 national net undercount in the 1990 census. This was one of the last acts of
 Bryant, who left her position on January 20,1993. Harry Scarr, Deputy
 Director, is now the senior official at the Census Bureau.

     "This decision was difficult to make," Bryant said in her notice to the
 Federal Renter. "It is the consensus of a committee of senior Census Bureau
 statisticians and demographers that adjustment would improve the accuracy of
 the 1990 census count at the national level, particularly for racial/ethnic
 and owner/renter groups. Adjustment would also more accurately depict most
 states' shares of the national population. The accuracy of the 1990 census
 is important to the intercensal adjustment issue because the 1990 figure is
 the startmg point for our yearly population estimates. However, because  the
 1990 total undercount is so small (less than 2 percent), it is impossible to
 accurately adjust for the 44,055 substate areas for which population
 estimates are produced."

     Bryant noted that sponsors of federal surveys conducted by the Census
 Bureau will be offered the option of calibrating their surveys to adjusted or
 unadjusted population estimates beginnmg in 1993. These would be such surveys
 as the Current Population Survey, the National Health Interview Survey, and
 the National Crime Victimization Survey. These national surveys are
 calibrated at large, aggregate levels where Census Bureau research shows
 adjusted estimates are on average more accurate.

     Bryant also pointed out that unadjusted estimates remain the official
 population totals. Federal law requires that the Census Bureau issue official
 totals for use in any federal program which allocates its funding based upon
 population estimates.  The Census Bureau provides official population
 estimates to states and counties in every year between decenrialcensuses and
 to subcounty areas every other year. Estimates of US population as of July 1,
 1992, were released on January 1,1993.

 * Reprinted with permission of the Association of Public Data Users (APDU)
   For membership information contact:

                             Susan Anderson
                             (609) 258-6025 or
                             (609) 258-6052
ABSTRACT


                Revised Estimates of the Population
                of Counties by Age, Sex, and Race:
                           1980 to 1989

 These data are revised estimates of the Population of the 3,141
 counties in the United States as defined in 1990, by 5-year age
 groups (age 0 to 4, 5 to 9,,,,,,,85 and over), sex (male,
 female), and modified race (White, Black, other races) for each
 year, July 1, 1980 through July 1, 1989.  These data differ from
 the Preliminary estimates of the Population of counties by age,
 sex, and race available earlier this year.  These revised
 estimates are for counties as defined in 1990.  These estimates
 are also consistent with actual intercensal estimates for the
 Nation by age, sex, and race and the actual intercensal estimates
 for states by age and sex to be released later this year.

 The revised estimates included in this release are developed by
 interpolating between special census files for April 1, 1980 and
 1990.  The interpolations were adjusted to be consistent with:
 1) revised intercensal estimates of the population of the nation
 by age, sex, and race; 2) intercensal estimates of the
 population of states by age-and sex; and 3) intercensal estimates
 of the total population of counties.

 The age and race data in the 1980 and 1990 Census data files
 which were used as anchor points in this methodology were
 modified to be consistent with other data sets.  The 1980 census
 data were further modified to be consistent with the 1990
 definition of counties and the race modification Procedures
 developed for 1990.  The race Classifications were modified in
 the 1980 and 1990 census files.  The 1980 and 1990 census data
 included persons classified as "Other race".  These people were
 not included in one of the specified racial categories listed on
 the census form.  The existence of the "Other race" category is
 inconsistent with race categories defined by the Office of
 Management and Budget in OMB Directive 15.  In order to serve the
 needs of the user community, it was necessary to assign each of
 these persons to a specified race.

 The age statistics for 1990 were modified to correspond with the
 April 1, 1990 census date.  A review of the detailed 1990 census
 information indicated that respondents tended to provide their age
 as of the date of completion of the questionnaire, not their age
 as of April 1, 1990.  In addition, there may have been a tendency
 for respondents to round up their age if they were close to
 having a birthday.  The age data were modified to correspond to
 the April 1, 1990 date.

 The interpo1ations between the 1980 and 1990 modified census data
 were adjusted to be consistent with: 1) the intercensal estimates
 of the population of the nation by age, sex, and race; 2) the
 intercensal estimates of the population of states by age and sex;
 and 3) the intercensal estimates of the total population of
 counties. The intercensal estimates for the population of the
 nation by age, sex, and race, each state by age and sex, and
 total population of each county are consistent with both the 1980
 and 1990 censuses as enumerated.  The latest set of l980-based
 (postcensal) estimates totals and by age, sex, and race were
 applied to the intercensal formula described in appendix I.  All
 intercensal State estimates are adjusted to be consistent with
 the independent national intercensal estimates of population.
 All intercensal county estimates are adjusted to be consistent
 with the corresponding state estimates.

 The data shown on this computer tape are unrounded.  However, the
 limitations of our methodology are such that we do not consider
 these data to be accurate to the last digit.
 METHODOLOGY

              METHOD FOR PRODUCING INTERCENSAL ESTIMATES
                OF THE POPULATION OF STATES: 1981-1989


 This appendix describes the methodology used to derive the
 intercensal estimates of the resident population of States,
 divisions, and regions for July 1, 1981 to 1989.

 The intercensals are consistent with the 1980 Census counts as
 published in the U.S. Census Summary, PC80-l-B1 and the 1990
 census modified counts. The latest set of 1981-90 postcensal
 (1980-based) State estimates were used in the intercensal formula
 described below.  The sum of the intercensal state estimates for
 each year was adjusted to be consistent with independent national
 estimates of tne intercensal population estimates.

 Algebraically, the intercensal procedure can be described as:

                                  t/10
              P  = Q  (P    /  Q  )
               t    t   10      10

 The formula above is describeed in terms of the following
 notations:
                  = time (years) elasped since
                    April 1, 1980, 0 <  t  < 10
                                     -     -

              Q  = postcensal estimaate at time t
               t

              P  = intercensal estimate at time t
               t


 so that

             Q  = P   =   actual census count as
              o    o      of April 1, 1980

             P   =  actual census count
              10    as of April 1, 1990


             Q   = postcensal estimate for
              10   April 1, 1990

 This procedure was also used in developing the annual intercensal
 population estimates for the United States.


 RECORD LAYOUT

 General Information

 This file contains revised estimates of the population of the
 3,141 counties (1990 geography) in the United States by five-year
 age groups (ages 0-4, 5-9, .85 and over), sex (male, female) and
 modified race (white, black, other race) for each July I date
 1980 through 1989.

Record Layout

           Contents                       Columns

 Year (2 digits, 80.....89)               1-2
 TIPS (State/County)                      3-7
 Race/Sex code  (1 white male             8
                 2 white female
                 3 black male
                 4 black female
                 5 other male
                 6 other female)
 Blank                                    9
 Age            0=4                       10-17
                5-9                       18-25
                10-14                     26-33
                15-19                     34-41
                20-24                     42-49
                25-29                     50-57
                30-34                     58-65
                35-39                     66-73
                40-44                     74-81
                45-49                     82-89
                50-54                     90-97
                55-59                     98-105
                60-64                     106-113
                65-69                     114-121
                70-74                     122-129
                75-79                     130-137
                80-84                     138-145
                85+                       146-153





This page last reviewed: Friday, July 25, 2014
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