Data, Information and Knowledge

This chapter introduces the basic concepts of medical informatics: data, information, and knowledge. Data are classified into various types and illustrated by concrete medical examples. The concept of knowledge is formalized in the framework of a language related to objects, properties, and relations within ontology. Various aspects of knowledge are studied and illustrated on examples dealing with symptoms and diseases. Several approaches to the concept of information are systematically studied, namely the Shannon information, the discrimination information, and the decision information. Moreover, information content of theoretical knowledge is introduced. All these approaches to information are illustrated on one simple medical example.