Uncertain Population Forecasting

Abstract

"Errors in population forecasts arise from errors in the jump-off population and errors in the predictions of future vital rates. The propagation of these errors through the linear (Leslie) growth model is studied, and prediction intervals for future population are developed. For U.S. national forecasts, the prediction intervals are compared with the U.S. Census Bureau's high-low intervals." In order to assess the accuracy of the predictions of vital rates, the authors "derive the predictions from a parametric statistical model and estimate the extent of model misspecification and errors in parameter estimates. Subjective, expert opinion, so important in real forecasting, is incorporated with the technique of mixed estimation. A robust regression model is used to assess the effects of model misspecification."

Stochastic population forecasts using functional data models for mortality, fertility and migration

“…They are generated through stochastic population renewal using the cohort-component method of population projection (Preston et al, 2001, pp.119-129). The forecast is achieved either analytically using the stochastic Leslie matrix (Lee and Tuljapurkar, 1994;Sykes, 1969;Alho and Spencer, 1985) or more simply by Monte Carlo simulation to produce a distribution of possible outcomes. In both approaches, it is necessary to specify the mean (or median), variance-covariance structure and distributional form for each demographic component.…”

Proyección estocástica de la mortalidad mexicana por medio del método de Lee-Carter / Stochastic Projection of Mexican Mortality through the Lee-Carter Method

“…En el aspecto metodológico ha habido algunos intentos por tomar en cuenta la incertidumbre inherente a toda prefiguración del futuro. Entre los principales trabajos sobre proyecciones estocásticas se encuentran los de Sykes (1969), Le Bras (1971), Saboia (1974Saboia ( y 1977, Heyde y Cohen (1985), Cohen (1986), Alho y Spencer (2005), Alho (1985Alho ( y 1990, Lee (1993Lee ( y 1974, Lee y Carter (1992), Lee y Tuljapurkar (1994) y, recientemente, Hyndman y Booth (2008).…”

“…Por otro lado, Alho y Spencer (2005), y Alho (1985Alho ( y 1990 proponen modelar el tamaño de los grupos por edad y sexo de acuerdo con funciones no-lineales de tasas vitales aleatorias; asimismo proponen una medida de volatilidad para la fecundidad. En trabajos más recientes, Alho ha propuesto una forma de pronosticar los componentes demográficos basándose en el uso de distribuciones de probabilidad conocidas así como de métodos bayesianos.…”

Point and interval forecasts of age-specific life expectancies

“…In recent years, many authors have provided interval forecasts to measure the uncertainty associated with the point forecasts; see for example, Lutz and Scherbov (1998) for Austria, Alho (1998) for Finland, Keilman and Pham (2000) for Norway, and Tayman, Smith, and Lin (2007) for the United States. These methods have been motivated by earlier work on stochastic forecasts, by for instance, Lee (1974), Stoto (1983), Alho and Spencer (1985), Alho (1990) and Lee and Tuljapurkar (1994). The current paper is a contribution to the literature in this area.…”