CASUEL is a Common Case Representation language developed in the INRECA project in 1992. INRECA (INduction and REasoning from CAses) is a case-based reasoning project funded by the European Union under ESPRIT-contract P6322.

CASUEL is the interface language between all the INRECA component systems, but it is also intended to serve (1) as the interface language between the INRECA integrated system and the external world, and (2) as a standard for exchanging information between classification and diagnostic systems that use cases. Currently, CASUEL is NOT designed to handle design and planning tasks.

CASUEL is a flexible, object-oriented frame-like language for storing and exchanging descriptive models and case libraries in ASCII files. It is designed to model naturally the complexities of real cases. CASUEL represents domain objects in a class hierarchy using inheritance, the slots used to describe the objects, typing constraints on slot values, as well as different kinds of relationships between objects. In its current version, CASUEL additionally supports a rule formalism for exchanging case completion rules and case adaptation rules, as well as a first mechanism for defining similarity measures.

CASUEL is more concise than flat feature-value vectors for the representation of objects with a large number of potentially relevant attributes of different types, only a few of which are applicable to any given case. Its use reduces the number of information gain calculations needed for induction systems or similarity computations required for case-based reasoning. However, CASUEL provides a lot of features, it does not require applications to use all of them. Therefore, CASUEL is a keyword- driven language, that allows different system component to ignore irrelevant definitions. On the other hand, CASUEL is also open in the sense that new features can be defined if necessary for a particular kind of application or component.

CASUEL is intended to become the European standard for exchanging case-bases. It is planned to use CASUEL as a starting point from which a more general (including also planning and design tasks) Case Interchange Format will be developed in a joint European CBR-activity.


CASUEL was developed 1992 in the INRECA project. INRECA was funded by the European Union under ESPRIT-contract P6322.


The Consortium consisted of four partners.

Research Team

One member of the Wi2-group have been working within CASUEL.