A Method for Estimating Size of Population Aged 90 and over with Application to the U.S. Census 2000 Data

In many countries population estimates are unreliable at higher ages. In this article a method for producing an independent estimate of population aged 90+ from data on deaths and population estimates at lower ages is developed. The method builds on an indirect mortality estimate from deaths only and on an estimate of rate of mortality change. Theoretical foundation and bias expected on application of this procedure to the real data are discussed as well. Testing of this method on accurate demographic data shows its superiority over available procedures. The method has been applied to the evaluation of size of population 90+ in the census 2000 of the United States. The results show a high degree of agreement between two estimates, but the possibility of slight overestimation of males in census data cannot be completely ruled out. To facilitate the application of this method, a computer program is provided as well.