Total methods of projection
Total methods of projection involve fitting a mathematical model to data on past trends in the size of the population and using the fitted model to extrapolate the population forward (or on occasion backward into the more distant past).
The main steps involved in the procedure are to:
- select an appropriate model of the growth process
- estimate the parameters of the model from past estimates of the population
- extrapolate the fitted curves and read off the projected population.
The following pages discuss four mathematical functions that can be used to model population growth:
- Zero popupulation growth
- Arithmetic growth
- exponential growth
- logistic growth