Evaluating Methods for Short to Medium Term County Population Forecasting

Public services provision and land use planning are crucially dependent on accurate population forecasts. Despite their importance, particularly for planning at the local level, population forecasts for Irish counties are not readily available. A number of different methods could be used to calculate such forecasts, but it is not clear which of these possible methods produces the most accurate forecasts. This paper assesses the data requirements and methodology involved in the implementation of the various techniques, and evaluates the forecasting performance of a number of different methods in terms of the forecast error associated with each method over the period 1991 to 1996. The results of this paper show that simple share extrapolation techniques perform well compared with the more elaborate cohort component model that is widely used for national projections.