New institutionalist approaches reflect a common commitment to the significance of institutional arrangements and a common criticism of atomistic accounts of social processes. Beyond these core assumptions, new institutionalism is characterized by a great variety of positions, which are sometimes complementary and sometimes conflicting. The different positions can be captured in six 'vignettes': the mythic institution, the efficient institution, the stable institution, the manipulated institution, the disaggregated institution, and the appropriate institution. The vignettes differ in the significance they accord to: formal and informal institutional rules; change and stability within institutions; and the role of rational action and norm-governed behaviour in creating and sustaining institutions. The comparative critical assessment of the vignettes can provide the basis for a multi-theoretic approach to the study of institutions and institutional change.