User interaction in decision support systems: the role of justification

Justification has a central role in the interaction between a user and a decision support system (DSS). Justification is aimed at supporting the user conviction that the output of a DSS is correct, reliable, and trustworthy, providing sound specific motivations and credible reasons. Therefore, it is a primary task for improving user acceptance, and making user interaction more effective and efficient. The paper discusses the concept of justification and proposes a classification of justification according to two dimensions: the relation of justification with the problem solving process used to derive the DSS conclusion´s (dependent or independent) and the representation of justification knowledge (explicit or implicit). Later, it analyzes the nature of justification knowledge, and provides a new model to represent teleological, causal and behavioral knowledge for justification. Finally two concrete examples are discussed, concerning a DSS that supports the chief melter in charge of controlling the operation of an arc furnace for steel production (CMSS and ExplainCMSS) and a DSS that assists physicians in the diagnosis of liver diseases (ISHeE)