Reference class forecasting (also called comparison class forecasting) is a method of predicting future outcomes by examining similar situations from the past.

Daniel Kahneman and Tversky found that human judgment is generally overoptimistic (See: Planning overconfidence). People often focus on the "inside view" – a perspective that concentrates on the specific details, plans, and circumstances of their situation. In contrast, the “outside view” (or reference class forecasting) involves comparing the current situation to a broader class of similar cases and using historical data to make more accurate predictions. This approach helps counter our tendency to ignore statistical and historical evidence.