Population Projections by Age for Florida and its Counties: Assessing Accuracy and the Impact of Adjustments

Publication Date: 
Wednesday, October 1, 2014

Projections of total population have been evaluated extensively, but few studies have
investigated the performance of projections by age. Of those that did, most focused on
projections for countries or other large areas. In this article, we evaluate projections by age for
Florida and its counties, as produced and published between 1996 and 2010 by the Bureau of
Economic and Business Research (BEBR) at the University of Florida. We first compare the
precision and bias of projections of total population with the precision and bias of projections by
age, at both the state and county levels. This is followed by a more detailed examination of
county-level projection errors for individual age groups, first in the aggregate and then
disaggregated by sex and population size. The second part of the analysis focuses on a number of
adjustments that were implemented in projections published in 2006 and 2009. Intended to
improve accuracy, these adjustments involved updates to the base population, fertility rates, and
survival rates. We compare the accuracy of projections incorporating these adjustments with the
accuracy of projections excluding them. We believe this study offers a unique opportunity to
examine a variety of characteristics regarding the forecast accuracy of small-area population
projections by age.

Publication Types: 
BEBR Division: