The value added by an organization’s IT assets is a critical concern to both research and practice. Not surprisingly, a large number of IS effectiveness measures can be found in the IS literature. What is not clear in the literature is what measures are appropriate in a particular context. In this paper, we propose a two- dimensional matrix for classifying IS effectiveness measures. The first dimension is the type of system studied. The second dimension is the stakeholder in whose interests the system is being evaluated. The matrix was tested by using it to classify IS effectiveness measures from 186 empirical papers in three major IS journals for the last nine years. The results indicate that the classifications are meaningful. This, in turn, means that the IS effectiveness matrix provides a useful guide for conceptualizing effectiveness measurement in IS research, and for choosing appropriate measures.