An Evaluation of Population Projections by Age

Abstract

A number of studies have evaluated the accuracy ofprojections of the size of the total population, but few have considered the accuracy of projections by age group. For many purposes, however, the relevant variable is the population of a particular age group, rather than the population as a whole. We investigated the precision and bias of a variety of age-group projections at the national and state levels in the United States andfor counties in Florida. We also compared the accuracy of state and county projections that were derivedfrom full-blown applications of the cohort-component method with the accuracy of projections that were derived from a simpler, less data-intensive version of the method. We found that age-group error patterns are different for national projections than for subnational projections; that errors are substantially larger for some age groups than for others; that differences in errors among age groups decline as the projection horizon becomes longer, and that differences in methodological complexity have no consistent impact on the precision and bias of age-group projections.Population projections are used for a wide variety of planning and budgeting purposes.

Population projections for all U.S. counties by age, sex, and race controlled to the Shared Socioeconomic Pathways

“…To In keeping with demographic tradition (Booth 2006;Smith and Tayman 2003;Smith et al 2006), I evaluate the projections using three primary statistics. To determine the overall accuracy of the projections, I use Absolute Percent Errors (APE) and to determine the bias of the projections I use the Algebraic Percent Error (ALPE).…”

“…Out-of-sample validation reveals errors on par with or better than cohort-component population projection models undertaken at the national and sub-national scale (Raftery et al 2012;Rayer 2008;Smith and Tayman 2003;Sprague 2012;Wilson 2016) (Table 5 summarizes several projection evaluations for comparison purposes).…”

Protocol for Candrive II/Ozcandrive, a multicentre prospective older driver cohort study

“…In North America as well as Australia and New Zealand, people over the age of 65 represent the fastest-growing segment of the population, with this age group predicted to constitute 20-25% of the population by 2030 (Australian Bureau of Statistics, 1999;Bell et al, 2011;Bongaarts, 2009;Canadian Study of Health and Aging, 1994;Demography Division, Statistics Canada, 2005;Smith and Tayman, 2003). As a result, the number of older people holding driver's licences has increased in both percentage and absolute terms (Dobbs, 2008;Lyman et al, 2002;Road Safety Program Office, Safety Policy & Education Branch, Ontario Ministry of Transportation, 2006;Transport Canada, 2011).…”

The Canadian Safe Driving Study—Phase I pilot: Examining potential logistical barriers to the full cohort study

“…Persons over the age of 65 years represent the fastest-growing segment of the Canadian population (Bell et al, 2011;Bongaarts, 2009;Smith and Tayman, 2003); likewise, the absolute number and proportion of older persons holding a driver's licence is increasing rapidly (Dobbs, 2008;Lyman et al, 2002). Chronic impairments associated with aging can lead to impaired driving ability Marshall, 2008).…”