This material is based upon work supported by the National Science Foundation under grant #SES-8410190. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessari y reflect the views of the National Science Foundation. This support was crucial to the completion of this project, and we are grateful for it. As is usually the case when doing academic research, we are also indebted to a number of individuals. Robert Gillingham, John Greenlees, Jack Triplett, and Paul Harte-Chen freely gave of their time to share their ideas concerning income-based cost of living indices. Seminar participants at the BLS, the University of Karlsruhe, and Tilburg University provided insightful comments on preliminary portions of the manuscript. Bill Stober provided encouragement, and Desmond Lo and Albert Tsui read parts of the manuscript. We owe a special thanks to Bert Balk for providing detailed handwritten comments on a preliminary draft. Evelyn Buchanan and Audrey Abel did an excellent job of typing and retyping numerous drafts of the manuscript. Finally, a very warm thanks to our wives, for enduring. CONTENTS Page PREFACE PART I.