Developing efficient and effective decision making support includes identifying means to reduce repeated manual work and providing possibilities to take advantage of the experience gained in previous decision situations. For this to be possible, there is a need to explicitly model the context of a decision case, for example to determine how much the evidence from one decision case can be trusted in another, similar context. In earlier work, context has been recognized as important when transferring and understanding outcomes between cases. The contribution of this paper is threefold. First, we describe different ways of utilizing context in an envisioned decision support system. Thereby, we distinguish between internal and external context usage, possibilities of context representation, and context inheritance. Second, we present a systematically developed context model comprised of five types of context information, namely organization, product, stakeholder, development method & technology, and market & business. Third, we exemplary illustrate the relation of the context information to architectural decision making using existing literature.