This book is the cuhnination of many years' research inspired by the pioneering and seminal works of Sah and Stiglitz. We gratefully acknowledge the influence of these two authors, whose ideas and contributions have brought us together on this collabo- ration, despite our divergent scientific backgrounds (while Catalani is interested in quantitative methods, Clerico is a non-quantitative economist) . We thank the Editor of the Rivista Internazionale di Scienze Economiche e Commerciali for permission to use slightly modified versions of papers published in that Review (they are the content of Chapters I and III of Part I, and of Chapter I of Part II). We heartily thank Ms. Laura McLean for carefully revising our English. The publication of this book has been made possible by a grant from the Department of Economics, University of Turin, Italy. Torino, July 1995 Mario S. Catalani Giuseppe F. CIeri co CONTENTS Introduction 1 PART I Some models of decision making structures I. How and when unanimity is a superior decision rule 15 II. Majority rules and efficiency of the decision process 31 III. Team cooperation vs. independent assessment 41 IV. Leadership and dependence 59 V. The decision making process of political organizations 75 PART II Pyramid decision structures I. Pyramidal structures: a preliminary note 91 II. Other properties of pyramids 103 III. Pyramids and dependence 117 IV. Organization, loyalty, and efficiency 133 Conclusions 151 References 163 Mario S.