Institutional theory rests on a rejection of reductionism. Instead of reducing higher-order phenomena to aggregates of behavior, institutional theory reverses this causal imagery. It attributes the behavior of organizations and nation-states to contextual factors, notably organizational fields, national institutional systems, or the emerging global polity, Institutionalists, particularly within sociology, also emphasize specifically cultural mechanisms for these higher-order effects. This article develops the methodological foundations for these claims. It surveys and elaborates research designs for documenting higher-order effects and for differentiating the cultural mechanisms of institutional influence. It also presents new strategies for assessing multiple logics and the coherence of institutional orders, moving beyond adoption and diffusion studies to analyze the dynamic and contested processes of institutionalization and institutional change.