prognostication

Prognostication is the act or practice of forecasting future events or conditions based on data, signs, models, or expert judgment. It covers a broad range of disciplines and methods and is often distinguished from mere speculation by its reliance on systematic reasoning, evidence, or probabilistic assessment. The term derives from Greek prognostikos, meaning foreknowledge, via Latin and English.

In medicine, prognosis is a related concept describing the likely course and outcome of a disease for an individual. Prognostication in non-medical contexts includes forecasting political developments, economic trends, weather, or technological changes. Historically, prognostication has included divination and astrology, which are now viewed as distinct from evidence-based forecasting.

Methods used to prognosticate include statistical modeling, time-series analysis, machine learning, probabilistic reasoning, scenario analysis, and expert judgment. Data sources vary by domain: weather data, economic indicators, epidemiological data, or social signals. Forecasts are typically expressed as probabilities or confidence intervals rather than certainties.

Limitations of prognostication include uncertainty, model assumptions, data quality, and the inherently probabilistic nature of many outcomes. Overconfidence, selection bias, and miscommunication of risk can reduce usefulness. Critics emphasize the distinction between prognostication and prescriptive predictions, noting that forecasts guide but do not determine outcomes.

See also: prediction, forecasting, prognosis, uncertainty, Bayesian statistics.