Predictability, complexity, and catastrophe in a collapsible model of population, development, and environmental interactions

More and more population forecasts are being produced with associated 95 percent confidence intervals. How confident are we of those confidence intervals? In this paper, we produce a simulated dataset in which we know both past and future population sizes, and the true 95 percent confidence intervals at various future dates. We use the past data to produce population forecasts and estimated 95 percent confidence intervals using various functional forms. We, then, compare the true 95 percent confidence intervals with the estimated ones. This comparison shows that we are not at all confident of the estimated 95 percent confidence intervals.

Key words:

• Population forecasting
• population confidence intervals
• population prediction intervals
• model complexity
• demographic economic and environmental interactions

Notes

I would like to thank the many people who helped to improve this paper, especially Charles Becker, John Hillas, Diane Macunovich, Stefan Mittnik, Lee Wexler, and an anonymous referee.