Medical informatics: reasoning methods.

The progress of medical informatics has been characterized by the development of a wide range of reasoning methods. These reasoning methods are based on organizing principles that make use of the various relations existing in medical domains: associations, probabilities, causality, functional relationships, temporal relations, locality, similarity, and clinical practice. Some, such as those based on associations and probabilities have been developed to the point where there are off-the-shelf tools available for the researcher to develop new decision support tools. Others such as temporal relations require more effort to use effectively. Even so, we have learned the importance of a separate explicit representation of the domain knowledge and have considerable experience and an impressive armamentarium with which to face the new milieu provided by the Internet.