Complexity, accuracy, and utility of official population projections

The level of complexity affects both the accuracy and their utility of official population projections used for government planning. This article examines the types of complexity in population projections, charts the growth of complexity in projections produced by the U.S. Census Bureau, and evaluates the accuracy of those projections. While increased complexity does not improve the accuracy or estimates of total population growth, it does appear to improve the accuracy of projected age distributions. Moreover, the value of these projections to the user depends upon many factors in addition to accuracy. Increasing complexity may improve some aspects of a projection's utility while degrading others.