Probability

European Definition

ENISA

Probability is the extent to which an event is likely to occur.

European Project Definitions

CIPRNet project

The CIPRNet project uses the following definition:

Probability is the measure of the chance of occurrence expressed as a number between 0 and 1, where 0 is impossibility and 1 is absolute certainty.

National definitions

Colombia

Probabilidad: Posibilidad de que algo ocurra bien sea que se haya definido, medido, o estimado objetiva o subjetivamente, o en términos de los descriptores generales (tales como raro, improbable, probable, casi cierto). La probabilidad puede expresarse cuantitativa o cualitativamente.

United Kingdom (UK)

Probability is used to describe the chance or relative frequency of particular types of event occurring.

It can also include sequences or combinations of such events.

United States

Likelihood that is expressed as a number between zero and one, where zero indicates that the occurrence is impossible and one indicates definite knowledge that the occurrence has happened or will happen, where the ratios between numbers reflect and maintain quantitative relationships.

Standard Definition

ISO Guide 73:2009

Measure of the chance of occurrence expressed as a number between 0 and 1 where 0 is impossibility and 1 is absolute certainty.

Other Definitions

Ontario (Canada)

Probability is the likelihood of an event occurring that may result in an emergency, disaster or service disruption.

Probabilité: survenance prévisible d’un événement susceptible de causer une situation d’urgence, un sinistre ou une perturbation de services.

See also

• Likelihood
• Risk