Rule-based systems can be viewed as possessing two sets of properties : static and dynamic . Static properties are those that can be evaluated without executing the system , and dynamic properties can be evaluated only by examining how the system operates at run time . The dynamic properties of a rule-based system have been largely neglected in validation and verification work done thus far . Structural verification and static testing techniques do not yield information on how a rule-based system achieves its goals at run-time , given a set of input data . This paper presents a model for the relationship between the goal states achieved by a rule-based system , the set of inter-related rules that must fire to achieve each goal state , and the data items required for the rules in the rule sequence to fire . Then , we describe a method for applying this model to study the dynamic properties of a rule-based system . It is demonstrated that this model permits the validation of dynamic properties of a rule-based system , enabling system developers to decide : (1) if the manner in which the system pursues goals is valid according to the specifications (and expectations) of the designers ; (2) what relationship exists between the quality of system output for a given test case and the goals achieved during problem-solving on that test case ; and (3) how the overall problem-solving activity of the system relates to the availability of input data .