- noun a model for decision-making, showing the possible outcomes of different decisions
- noun a graphical representation of a decision table showing possible paths and actions if different conditions are met
- A diagram in which the possible outcomes of a problem, with sequential alternatives, are represented as branches. As each decision is made, two or more branches, representing the next choices, become available. This continues until a conclusion is reached.
- (written as Decision Tree)A diagrammatic representation of a decision analysis in which chains of choices are identified, each conditional on a prior choice and with outcomes and probabilities built in. In the diagram, ■ indicates a decision node, ● indicates a chance node and b indicates an end or terminal node. In this decision tree, the issue is whether to give therapy. If it is given (the Rx group), there is a probability p of life and of 1 - p of death. In the untreated (control) group there is a probability r of life and 1 - r of death. The surviving patients in either arm may become in-patients or treatment may no longer be needed beyond a certain point. If the costs of the therapy are known, and the probabilities of life or death, and the probabilities that living patients will become hospitalized or no longer need treatment, together with the costs of these options (for both arms), then the (probable) cost-effectiveness of the two courses of action may be computed.