Balking A queuing theory term for a situation where customers are 'lost' if all servers are occupied when they arrive.
Chance node A point at which a decision tree branches into a mutually exclusive set of states of nature. A chance node is usually represented by a circle.
Cognitive mapping A term from psychological research on perception which describes the general task of mapping a person's thinking. A cognitive map is not simply a 'word and arrow' diagram or an influence diagram; it is the product of a formal modelling technique with rules for its development.
Constraints Upper or lower limits on the level of a particular activity.
Corporate needs assessment A more or less formal process for adjusting the provision of health services in response to pressures for change from providers, central policy makers, professional bodies, patients and representatives of the public.
Customers Anyone or anything that requires a service or processing. Examples are outpatients receiving treatment, or blood samples to be tested.
Decision Analysis An approach to decision making which involves representing the problem in decision-tree form, branching at decision nodes and chance nodes. Probabilities are needed for each branch out of a chance node and utilities for each final branch in the tree.
Decision area Any area of choice within which decision makers can conceive of an alternative course of action that might be adopted, now or at some future time.
Decision criteria Characteristics used in judgements about preferences, or measures of performance, against which decision options are assessed. They usually relate to benefits or achievement of objectives; to cost or risks; and to feasibility.
Decision node The point in a decision tree where a decision must be made between competing and mutually exclusive policy or treatment options.
Decision outcome A combination of decision options and states of nature. Each 'terminal' branch of the decision tree represents an outcome.
Decision tree A type of model of a decision making problem with branches representing the possible decision options and states of nature.
Deterministic models Models in which it is assumed that the nature of the relationships between variables is known with certainty so that ('chaotic' systems excepted) for a given set of starting values, the results are always the same.
Diagnosis related groups (DRG) Classification system that assigns patients to categories on the basis of the likely cost of their episode of hospital care. Used as a basis for determining level of prospective payment by purchaser.
Dominated option A decision option that may be similar to another option in terms of some criteria but is inferior to it in others.