Adjusting the Age Distribution of the Population Age 85 and over in the 1990 Census

Monique B. Williams, U.S. Census Bureau

Between 1950 and 1970, the population over age 85 in the United States increased 161 percent with an annual growth rate (r) of 0.0481. From 1970 to 2000, the population increased another 181 percent while the age-specific annual growth rate declined slightly to 0.035. Given the salience of the change in the United States’ age distribution for public policy, quality data on the age structure is important in order to understand the causes and consequences of population aging. This paper attempts to assess the quality of the Census data at ages 85 and over by evaluating the 1990 Census enumeration and comparing census results with estimates derived independently from Medicare and the National Center for Health Statistics data on deaths. Specifically, I use the method of extinct generations to estimate the April 1, 1990 population with data from the NCHS vital registration and from the Social Security Administration Medicare enrollee death database. The results of this evaluation are compared to other studies that indicate that Census data are flawed at the oldest ages (Rosenwaike 1968; Rosenwaike 1979; Coale and Kisker, 1990; Das Gupta, 1990). References Coale, A. J. and E. E. Kisker (1990). "Defects in Data on Old-Age Mortality in the United States: New Procedures for Calculating Mortality Schedules and Life Tables at the Highest Ages." Asian and Pacific Population Forum 4(1): 1-32. Das Gupta, P. (1990). Reconstruction of the Age Distribution of the Extreme Aged in the 1980 Census by the Method of Extinct Generations. Social Statistics Section American Statistical Association. Rosenwaike, I. (1968). "On Measuring the Extreme Aged in the Population." Journal of the American Statistical Association 63(321): 29-40. Rosenwaike, I. (1979). "A New Evaluation of the United States Census Data on the Extreme Aged." Demography 16(2): 279-288.