AbstractDespite a history of successful applications to operational-level problems, the vale of OR/MS modelling techniques as aids in policy/strategy formulation has not been widely demonstrated. In this paper, we suggest that the language of traditional OR/MS model structures is too restrictive to deal with issues typically confronted in policy-making. Differences between operational-level decision-making processes and policy/strategy formulation processes are discussed; alternative model structures are described and classified; and a modelling language for addressing issues of policy and strategy is proposed. The language is presented in set-theoretic terms, and the resulting structure implies that certain model classes accommodate policy-level management needs better than others. Furthermore, policy-level models must serve a role distinct from the prediction and optimization role typically served by operational-level models.