Design science research (DSR) for Information Systems (IS) aims to provide innovative solutions for classes of organizational problems that involve Information Technology. Discussions on what constitutes the core of the discipline and what are valid research outcomes have continued throughout its evolution. A well-designed outcome classification delivers an organizing foundation that has benefits such as structured access to research results and standardization of terms and concepts. Our analysis of existing DSR outcome classifications finds them often to be intuitive and coarse, with differences in constituents, decompositions, granularity, and scope, and with semantics that may drift over time. To improve on this and achieve a well-designed classification, we employ established methods for typology and taxonomy design, which focus on the dimensions along which types are created. For identifying these types, we analyse key concepts that constitute the theoretical core of DSR, as well as the structure of existing classifications. Conceptual designs are difficult to validate experimentally. We describe subsequent design iterations and the reasoning behind these, harmonize across existing classifications, and describe feedback from insights gained from using it in teaching. We assess against criteria developed for artefact and taxonomy soundness, and validate by classifying artefacts reported in recent research conferences.