In a relevance diagram, a deterministic node is a degenerate chance node representing a deterministic variable. The deterministic variable associated with a deterministic node can be viewed as an uncertain variable having a probability distribution totally concentrated on a single outcome. A deterministic node is drawn as a double bordered oval or circle. Typically, the deterministic node is internally represented by a table or a function. Recognizing a node's determinism can greatly simplify and speed its formulation and assessment. [Evaluating a Relevance Diagram|Relevance diagram evaluation]] algorithms can also be very efficient when they recognize deterministic nodes.

See also: Asymmetric Decision Basis and Coalescence.