Information from professionals about how they actually operate at each stage of the settlement process is translated by the computer model into decision rules which, taken together, determine how far the case goes along the bargaining sequence leading to the courtroom, and at what dollar amount (if any) the matter is settled. The many rules, reflective of the legal and economic complexities involved, are arrayed in decision trees that represent the 'if-then' relationships that determine a litigator's decisions and behavior. A chaining of these rules represents the entire reasoning process by which a litigator's action evolves, with the conclusions of some rules serving as the premises of subsequent ones. Incorporated into a computer program, these rules constitute a model that replicates litigators' reasoning processes in a variety of situations. The specific facts of a case determine the rules to be used; if a material fact is changed, the chain of rules for that case also changes. The rule-based model can be refined by asking litigators to review the existing patterns, which can then be accordingly modified or elaborated. The model can be validated by comparing rule-based models of settlement decisions with actual settlements. Further research is required, but this prototype does indicate that at least some aspects of the settlement process can be described by rule-based models. A 45-item bibliography is provided; charts and footnotes are given. The appendixes include a representative set of rules and a trace of a user interaction with the prototype system. (Author summary modified)