unlikeliness

Unlikeliness is the quality or state of being unlikely—the condition of having a low probability of occurring. It is a relative judgment that depends on the reference class, available evidence, and the context in which the assessment is made.

In everyday use, unlikeliness describes events that are not expected to happen. The degree of unlikeliness is subjective and can vary with new information or changes in assumptions.

In formal probability, likelihood and probability quantify how probable an event is; unlikeliness is not a formal term, but a low-probability event may be described as unlikely or improbable. The complement rule applies: the probability of not occurring is 1 minus the probability of occurring.

Cognitive processes influence judgments of unlikeliness. Biases such as the availability heuristic can make rare events seem more or less likely than statistics suggest, affecting risk assessment and decision making.

Etymology and usage: the word arises from un- plus likely, with unlikeliness as the noun form. It appears in journalism, analysis, and philosophy to characterize low-probability outcomes or events that defy expectations.

See also: improbability, probability, likelihood, rare event.