Prediction and Forecasting

Political forecasting and prediction refers to any effort to anticipate events that will occur at a future point in time, usually with the intention of determining actions that will either exploit or mitigate the effects of those events. Forecasting is implicit in almost all political decision making, but the techniques vary widely in their level of explicitness, ranging from simple intuition to detailed historical analogies to elaborate statistical models. This entry discusses the sources of regularity in political behavior; conditional and unconditional forecasts; the concepts of forecast horizons, windows, and specificity; modes of traditional (nontechnical) forecasting; and simulation and statistical approaches to technical forecasting.

Evidence for the importance of forecasting to political elites can be found in some of the earliest available records of organized human behavior, such the biblical story of Joseph interpreting the dreams of an Egyptian Pharaoh found in Genesis 41. A wide variety of divination methods—for example, augury, astrology, dream interpretation, and consultation with oracles—were nearly universal across cultures in premodern times, and practitioners in these fields often enjoyed high official status. These supernatural techniques were gradually supplemented with the use of historical analogies and collections of aphorisms or “wisdom literature,” but prediction techniques remained nontechnical until relatively recently.

The prospect of systematic forecasting of political behavior became attractive following the development of highly accurate forecasting models of physical phenomena, particularly the example of Isaac Newton's laws of motion in the 17th century, and the next 2 centuries saw the production of a number of works on “laws” of political and economic behavior that were effectively forecasting models. However, the systematic development of reasonably accurate numerical forecasts did not occur until the development of modern statistics in the early 20th century. With the increase in communication and computing power, accurate technical forecasts in some domains, most conspicuously election outcomes, were common by the late 20th century, and the methods are now being extended to other types of behavior, notably forecasts of political instability.