A Probabilistic Basis (or probabilistic decision basis, or probabilistic model) is a formal probabilistic model of a decision. A probabilistic basis (which is typically implemented as a relevance diagram—referred to as the basic relevance diagram) explicitly represents the important decisions and uncertainties that constitute the overall decision at hand. A probabilistic basis includes the decision-maker's value model and utility function.

See also: Decision Basis, Decision Variable, Deterministic Basis and Uncertain Variable.