Early versions of this paper were presented at the on Institutional Change, held at the Center for Advanced Study in the Behavioral Sciences, Stanford, CA, May 15-16, 1987; and at a conference, Critical Perspectives on Organizational Theories, sponsored by the International Sociological Association and held at the Conference Center De Narwal, Wassenaar, The Netherlands, July 19-21, 1987. Thanks are due to the conference organizers: Paul J. DiMaggio and Walter W. Powell, Stanford Conference; and to Marshall W. Meyer and Ad Teulings, Wassenaar Conference. I also wish to acknowledge the helpful comments received on earlier versions of this paper from Ronald L. Jepperson, John W. Meyer, and Walter W. Powell.