The effect of formal representations on the quality of legal decision making

Accessibility of legal sources is crucial to both jurists and citizens. As the development of E-government is speeded up the number of legal information systems including knowledge-based services is likely to increase accordingly. In the Program for an Ontology-based Working Environment for Rules and legislation (POWER) the Dutch Tax and Customs Administration (Belastingdienst) developed a formal model- ling approach for modelling legal sources. The results of applying this modelling pro- cess are formal models expressed in UML/OCL which can be used as the basis for amongst others verification, simulation and application generation. Since the legal knowledge to be applied in the operational units and on the Web is represented in these formal models, their quality needs serious attention. To be able to determine their quality, inspection by (legal) experts should be possible (validation). In most cases however these experts are not able to read these UML/OCL-models. Therefore a representation is required that can easily be derived from these models and that is easy to understand. Based on previous research we compared two different knowledge representations and tested their learnability and usability. Furthermore we examined the effect of rep- resentation on legal decision-making. The two representation-forms used are produc- tion rules and scenarios. The results of our experiment show that the performance of scenarios is significantly better then the performance of production rules.