An anomaly is a recurring pattern in economic data or decision-making that conflicts with the prediction of a benchmark model.
Why anomalies matter
Economists use models to organize evidence. When a regular pattern keeps showing up but the model says it should not, researchers have to decide whether the problem comes from behavior, frictions, omitted variables, or measurement.
Examples
Anomalies are always relative to a specific benchmark. Common examples include:
- the Allais paradox against expected utility,
- present-biased saving behavior against exponential discounting,
- persistent return patterns against simple market-efficiency benchmarks,
- slow price adjustment against fully frictionless models.
Some anomalies lead to better theory. Others fade once the data, risk adjustment, or sampling procedure improves.
A caution about evidence
Not every surprising result is a true anomaly. Data mining, publication bias, and weak identification can generate patterns that do not survive replication. That is why economists treat anomalies as prompts for investigation, not instant proof that a whole theory is wrong.