One of the arguments for using information systems (IS) is the expectation to enhance decision quality and, thereby, to increase overall business value. Practical experiences as well as empirical evidence show that this expectation is not always fulfilled and explanations are manifold. The paper applies information economics and, especially, agency theory as explanatory framework for analyzing the relation among IS and decision quality. Thereby, novel insights for unfulfilled expectations related to effects of IS on decision quality are derived. The paper seeks to substantiate the claim for an intensified agency-based research into IS - not only to enrich the IS discipline but also to indicate that agency-based research on management information could benefit from the IS discipline.