Trend Intra- & Extrapolation


Online Foresight Guide

The basis of trend extrapolation is to locate a trend that is apparent over time, and project it forward based on data concerning the rates of change and the extent of change achieved. In shorter-term forecasts this is often a matter of extending a linear or exponential curve (e.g. economic growth, power or diffusion of a technology). In the longer-term, limits to growth will often be encountered – there may be a limit to the size of the population to which a technology or cultural practice can diffuse for example, and various other types of trend curve may be fitted to the data (for example, the well-known s-shaped logistic curve).

Some of the issues affecting trend extrapolations are: