A DICTIONARY Epidemiology Fifth Edition Edited Miquel Porta REA A HANDBOOK SPONSORED BY THE LEA
Dictionary Epidemiology Fifth edition Edited for the International Epidemiological Association Miquel Porta Professor of Preventive Medicine Public Health School of medicine, Universitat Autonoma de barcelona Senior Scientist, Institut Municipal d Investigacio Medica Bare Adjunct Professor of Epidemiology, School of Public Health University of North Carolina at Chapel Hill Sander greenland John M. Last OXFORD UNIVERSITY PRESS
A Dictionary of Epidemiology of Fifth Edition Edited for the International Epidemiological Association by Miquel Porta Professor of Preventive Medicine & Public Health School of Medicine, Universitat Autònoma de Barcelona Senior Scientist, Institut Municipal d’Investigació Mèdica Barcelona, Spain Adjunct Professor of Epidemiology, School of Public Health University of North Carolina at Chapel Hill Associate Editors Sander Greenland John M. Last 1 2008
OXFORD UNIVERSITY PRES Oxford University Press, Inc, publishes works that further Oxford Universitys objective excellence th scholarshi p, and education Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi Shanghai Taipei Toronto With offices in Argentina Austria Brazil zech Republic France Greece Guatemala Hungary Italy Poland Portugal Singapore Copyright o 1983, 1988, 1995, 2001, 2008 International Epidemiological Association, Inc. Published by Oxford University Press, Inc 198 Madison Avenue. New York. New York 10016 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, ithout the prior permission of Oxford University Press. This edition was prepared with support from Esteve Foundation(Barcelona, Catalonia, Spain) Library of Congress Cataloging-in-Publication Data dictionary of epi edited for the International Epidemiological Association by Miquel Porta; associate editors, John M. Last.[ et al. ]-5the p cm. Includes bibliographical references and index ISBN978-0-19-5314496ISBN978-0-19-531450-2(pbk) 1. Epidemiology-Dictionaries I Porta, Miquel- I. International Epidemiological Association. A651D5532000 614403-dc2100-037504 246897531 Printed in the United States of America
Oxford University Press, Inc., publishes works that further 1 Oxford University’s objective excellence in research, scholarship, and education Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi Shanghai Taipei Toronto With offi ces in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Copyright © 1983, 1988, 1995, 2001, 2008 International Epidemiological Association, Inc. Published by Oxford University Press, Inc. 198 Madison Avenue, New York, New York 10016 www.oup-usa.org All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. This edition was prepared with support from Esteve Foundation (Barcelona, Catalonia, Spain) (http://www.esteve.org) Library of Congress Cataloging-in-Publication Data A dictionary of epidemiology / edited for the International Epidemiological Association by Miquel Porta; associate editors, John M. Last . . . [et al.].—5th ed. p. cm. Includes bibliographical references and index. ISBN 978–0-19–531449–6 ISBN 978–0-19–531450–2 (pbk.) 1. Epidemiology—Dictionaries. I. Porta, Miquel– II. International Epidemiological Association. RA651.D553 2000 614.4′03—dc21 00–037504 2 4 6 8 9 7 5 3 1 Printed in the United States of America on acid-free paper
Foreword TO WRITE A DICTIONARY IN ANY SCIENTIFIC DISCIPLINE IS A RISKY ENDEAVOR. BECAUSE scientists often disagree. The nature of science is not to reach consensus but to advance our knowledge by bringing conflicting ideas to critical examinations. That is true also for how we define the concepts we use. No dictionary will ever be able to satisfy all, nor should it try to he aim of the International Epidemiological Association(IEA)in cosponsor- ing this dictionary in its more than 20 years history has been to facilitate commu- nication among epidemiologists--to develop a"common language"to the extent that this is possible. We need a common language when we write papers, teach and communicate findings to the public This“ common lar nguage anges over time, as anybody can see by reading the successive editions of this dictionary. The language changes because our understanding of the concepts changes over time and new research options bring forward From the iea. we want to thank john Last for his tremendous achievements as editor of the dictionary, and we are happy to welcome Miquel Porta as the new editor. Miquel has provided the smooth transition we were looking for, and we are pleased to see that he continues the tradition of collaborating with leading epidemiologists worldwide to get the best possible result Jorn Olsen, Neil Pearce, and chitr Sitthi-Amorn Current, coming, and past presidents, International Epidemiological Association
To write a dictionary in any scientifi c discipline is a risky endeavor, because scientists often disagree. The nature of science is not to reach consensus but to advance our knowledge by bringing confl icting ideas to critical examinations. That is true also for how we defi ne the concepts we use. No dictionary will ever be able to satisfy all, nor should it try to. The aim of the International Epidemiological Association (IEA) in cosponsoring this dictionary in its more than 20 years’ history has been to facilitate communication among epidemiologists—to develop a “common language” to the extent that this is possible. We need a common language when we write papers, teach, and communicate fi ndings to the public. This “common language” changes over time, as anybody can see by reading the successive editions of this dictionary. The language changes because our understanding of the concepts changes over time and new research options bring forward new concepts. From the IEA, we want to thank John Last for his tremendous achievements as editor of the dictionary, and we are happy to welcome Miquel Porta as the new editor. Miquel has provided the smooth transition we were looking for, and we are pleased to see that he continues the tradition of collaborating with leading epidemiologists worldwide to get the best possible result. Jørn Olsen, Neil Pearce, and Chitr Sitthi-Amorn Current, coming, and past presidents, International Epidemiological Association www.ieaweb.org Foreword v
Foreword to the fourth edition 2001 IF I HAD TO LIMIT MY PROFESSIONAL BOOKCASE TO A SINGLE VOLUME. I WOULD choose this dictionary. With many new entries, updates, and other refinements in the fourth edition, the dictionary has grown from the original slim pocket book into a mature and substantial volume. John Last and his collaborators must be congratulated for their extraordinary devotion and productivity over the past 20 years, from which epidemiologists around the world have benefited. The dictionary's authority stems from its international recognition. It is an mmediate source for students and practitioners to verify their understanding of the increasing number of technical words in epidemiologic practice. It clarifies concepts that may not have been understood in class, fills many gaps in anyone's education, and jogs the memory of near-forgotten terms. It has no equal in the field of epidemiology The International Epidemiological Association is proud to have had such a ong-standing association with the dictionary. We all hope this relationship will continue indefinitely in the future, even though John Last, being mortal, will not He has set a high standard for his successors. We are grateful that he has prepared the way so well to ensure that the dictionary remains of contemporary relevance e coming decade Charles du v Florey International Epidemiological Association www.ieaweb.org
If I had to limit my professional bookcase to a single volume, I would choose this dictionary. With many new entries, updates, and other refi nements in the fourth edition, the dictionary has grown from the original slim pocket book into a mature and substantial volume. John Last and his collaborators must be congratulated for their extraordinary devotion and productivity over the past 20 years, from which epidemiologists around the world have benefi ted. The dictionary’s authority stems from its international recognition. It is an immediate source for students and practitioners to verify their understanding of the increasing number of technical words in epidemiologic practice. It clarifi es concepts that may not have been understood in class, fi lls many gaps in anyone’s education, and jogs the memory of near-forgotten terms. It has no equal in the fi eld of epidemiology. The International Epidemiological Association is proud to have had such a long-standing association with the dictionary. We all hope this relationship will continue indefi nitely in the future, even though John Last, being mortal, will not. He has set a high standard for his successors. We are grateful that he has prepared the way so well to ensure that the dictionary remains of contemporary relevance in the coming decades. Charles du V. Florey President, 1999–2002 International Epidemiological Association www.ieaweb.org Foreword to the Fourth Edition, 2001 vii
Preface THERE WAS VIRTUALLY NO GOOGLE, AND NO WIKIPEDIA THEN SEEMINGLY CENTURIES ago, when the previous edition of this dictionary came out in 2001. And of the respected dictionaries, very little was"posted on the Internet. Hard to believe. How did we manage, how could we ever have worked? But we did, we surely did: with open minds, critical sense, intellectual rigor.. No google or wiki or nformation technology (Ir) whatsoever will change that. The need to do the epidemiological work with"that Now we have thousands of webs and wikis with millions of papers, definitions, and discussions regarding terms at ourvery fingertips. Many are truly authoritative. You'll find them-some, selected-duly referenced at the end of this book.Yes, we googled and used the wikipedia, ""surfed"and"visited"many remote, beautiful places. To surf, to post . whew, these terms will soon be obsolete, won't they? We continue to seek and to find meaning: in PubMed/Medline, in online textbooks and websites. Foremost, within the main dictionaries, -which we read often while writing this new edition, and which I hope you will always use in case of doubt or simply to enrich the definitions that we offer here(See pages 265 and 273-289. At-and through-"places"such as High Wire, ScienceDirect Scopus, SciELO, ProQuest, Synergy, ISI Web of knowledge, Google, Yahoo, Live Search.. what yesterday was an unthinkable utopia has become an "achievable utopia, "in many places actually achieved daily: the infinite library, and with it the unlimited dictionary too. I wish Borges were alive to enjoy it, if not actually to see it. since he was blind So what sense does it make, to craft a dictionary? Simple: in a radically new way, the"IEA dictionary, ""Lasts dictionary"can be as relevant--or more so as it has been before. Because we have again, as always, critically listened and read, thought, discussed, and selected terms, meanings and definitions. With"that open minds, critical sense, common sense, intellectual rigor, creativity, flexibility, raftsmanship. . And because nowadays, with more"noise "than ever in history, sifting, decanting-selection with"that-is more valuable than ever before. You will judge, but writing this dictionary confirmed to me that it was perfectly feasible to achieve a normative purpose and an informative one. With help of the highest possible academic level from many colleagues(duly acknowledged later), I tried to integrate two approaches to dictionary making: expert-opinion-based prescription (to aid production) and corpus-based description(to aid decoding).Meanings of scientific terms need to be proposed and may occasionally be imposed--on the basis of expert advice; yet expert
There was virtually no Google, and no Wikipedia then, seemingly centuries ago, when the previous edition of this dictionary came out in 2001. And of the respected dictionaries, very little was “posted on the Internet.” Hard to believe. How did we manage, how could we ever have worked? But we did, we surely did: with open minds, critical sense, intellectual rigor. . . . No google or wiki or information technology (IT) whatsoever will change that. The need to do the epidemiological work with “that.” Now we have thousands of webs and wikis with millions of papers, defi nitions, and discussions regarding terms at our very fi ngertips. Many are truly authoritative. You’ll fi nd them – some, selected – duly referenced at the end of this book. Yes, we googled and used the Wikipedia, “surfed” and “visited” many remote, beautiful places. To surf, to post . . . whew, these terms will soon be obsolete, won’t they? We continue to seek and to fi nd meaning: in PubMed/Medline, in online textbooks and websites. Foremost, within the main dictionaries,1–3 which we read often while writing this new edition, and which I hope you will always use in case of doubt or simply to enrich the defi nitions that we offer here (See pages 265 and 273–289). At—and through—“places” such as HighWire, ScienceDirect, Scopus, SciELO, ProQuest, Synergy, ISI Web of knowledge, Google, Yahoo, Live Search . . . what yesterday was an unthinkable utopia has become an “achievable utopia,” in many places actually achieved daily: the infi nite library, and with it the unlimited dictionary too. I wish Borges were alive to enjoy it, if not actually to see it, since he was blind. So what sense does it make, to craft a dictionary? Simple: in a radically new way, the “IEA dictionary,” “Last’s dictionary” can be as relevant—or more so— as it has been before. Because we have again, as always, critically listened and read, thought, discussed, and selected terms, meanings and defi nitions. With “that”: open minds, critical sense, common sense, intellectual rigor, creativity, fl exibility, craftsmanship. . . . And because nowadays, with more “noise” than ever in history, sifting, decanting—selection with “that”—is more valuable than ever before. You will judge, but writing this dictionary confi rmed to me that it was perfectly feasible to achieve a normative purpose and an informative one. With help of the highest possible academic level from many colleagues (duly acknowledged later), I tried to integrate two approaches to dictionary making: expert-opinion-based prescription (to aid production) and corpus-based description (to aid decoding).395 Meanings of scientifi c terms need to be proposed —and may occasionally be imposed—on the basis of expert advice; yet experts Preface ix
Preface and specialists can also keep an ear for actual usage, from which meanings must also be extracted. When we were choosing terms and meanings, we not only kept epidemiological theory and general logic in mind, but usage as well, and often attested explicitly the different uses of polysemic terms. The word"dictionary"is itself notoriously polysemic. 3 This book shows how comfortable the coexistence healthy"micropolysemic"variation in the terms and definitions. This edition also reflects, I believe, how plural--professionally, scientifically, culturally, and ideologically--epidemiologists are John Last's outstanding first four editions were themselves the result of a highly comprehensive and inclusive process of selection of terms and definitions: some 20 years of fantastic collaborative work by several hundred contributors since the early 1980s. The five editions are an extraordinary"record-a"DVD, if you wish, or an"mp4-of the evolution of epidemiology during the last quarter century. I think they are also excellent materials for a sociology of epidemiology Therefore, as we continued the process and revised the last edition, we kept ell in mind many types of reader, most with unimaginable resources, smart, IT-wise. Although you are cordially invited to pull the many strings that this book holds by simply reading and turning its pages with your fingers(odd and familiar as this may at once seem), we assumed that these pages were just a stop on your journey: perhaps you just came here from Oxford Reference Online and will next be at The Cochrane Library. Who could know? You know Not only can you always expand and progress on what you find here, we know you can always assess, contrast, verify. Quite a responsibility for an editor of a dictionary. This duty is not new, but it surely works on a different scale nowa days. It is now so easy to find that we were wrong, narrow-minded, off beam too punctilious In the meantime, the ancestral book and our beloved library have not died. Neither did the paper journal. News of the death of academic journals--loudly proclaimed in the early years of this, the long awaited twenty-first century-were premature. We therefore may hope that this book will again find a place in your mind and be close to your heart. It's light in weight, its pages will welcome your handwriting, it can be comfortably read out there in the sunlight-batteries are not needed My call for contributions to this 5th edition was widely disseminated beginnin early in 2006--prominently, in the International Journal of Epidemiology and he Newsletter of the International Epidemiological Association(IEA), the worldwide scientific organization of epidemiologists that has nurtured all editions. The call was operationally answered by 224 professionals who registered in the wiki that we had set up with Oxford University Press. When invited to choose the sentence that best described their professional relationship with epidemiology, 67% of respondents selected"I have some to extensive training in epidemiology
and specialists can also keep an ear for actual usage, from which meanings must also be extracted. When we were choosing terms and meanings, we not only kept epidemiological theory and general logic in mind, but usage as well, and often attested explicitly the different uses of polysemic terms. The word “dictionary” is itself notoriously polysemic.395 This book shows how comfortable the coexistence of diverse meanings of “dictionary” can be. More importantly, it also shows a healthy “micropolysemic” variation395 in the terms and defi nitions. This edition also refl ects, I believe, how plural—professionally, scientifi cally, culturally, and ideologically—epidemiologists are. John Last’s outstanding fi rst four editions were themselves the result of a highly comprehensive and inclusive process of selection of terms and defi nitions: some 20 years of fantastic collaborative work by several hundred contributors since the early 1980s. The fi ve editions are an extraordinary “record” —a “DVD,” if you wish, or an “mp4”— of the evolution of epidemiology during the last quarter century. I think they are also excellent materials for a sociology of epidemiology. Therefore, as we continued the process and revised the last edition, we kept well in mind many types of reader, most with unimaginable resources, smart, “IT-wise.” Although you are cordially invited to pull the many strings that this book holds by simply reading and turning its pages with your fi ngers (odd and familiar as this may at once seem), we assumed that these pages were just a stop on your journey: perhaps you just came here from Oxford Reference Online and will next be at The Cochrane Library. Who could know? You know. Not only can you always expand and progress on what you fi nd here, we know you can always assess, contrast, verify. Quite a responsibility for an editor of a dictionary. This duty is not new, but it surely works on a different scale nowadays. It is now so easy to fi nd that we were wrong, narrow-minded, off beam, too punctilious . . . In the meantime, the ancestral book and our beloved library have not died. Neither did the paper journal. News of the death of academic journals—loudly proclaimed in the early years of this, the long awaited twenty-fi rst century—were premature. We therefore may hope that this book will again fi nd a place in your mind and be close to your heart. It’s light in weight, its pages will welcome your handwriting, it can be comfortably read out there in the sunlight—batteries are not needed. * * * My call for contributions to this 5th edition was widely disseminated beginning early in 2006—prominently, in the International Journal of Epidemiology and the Newsletter of the International Epidemiological Association (IEA), the worldwide scientifi c organization of epidemiologists that has nurtured all editions. The call was operationally answered by 224 professionals who registered in the wiki that we had set up with Oxford University Press. When invited to choose the sentence that best described their professional relationship with epidemiology, 67% of respondents selected “I have some to extensive training in epidemiology Preface x
Preface and currently work or have professional experience as an epidemiologist you may also have professional experience in other fields, "27% answered"While my main job is not as an epidemiologist, I often use epidemiologic knowledge, methods or reasoning in my work, " 2% selected"I have little to no training in epidemiology and I seldom or never use it in my work lyour contribution nevertheless welcomed, "and 4%"Other. " These data provide a factual back ground for the next paragraphs. Is this dictionary an attempt to demarcate epidemiology neatly? I dont think oOr Id rather think it is not, to the extent that a dictionary can-or needs to-avoid demarcating a discipline. 4 Yet like many other scientists, every now and then epidemiologists engage in boundary-making endeavors and disciplinary demarcation. And then, as usual in other disciplines, epidemiologists assert or reclaim contested epistemic authority and may claim jurisdiction over areas of public health, medicine, statistics, or science. These efforts evolved in the course of the twentieth century while epidemiology developed as a very diverse, eclectic- and foremost, integrative-field of practice and academic discipline. -l2 And so will they evolve as the societies of the twenty-first century continue developing There is nothing wrong with that, it is the natural thing Is this dictionary an epistemic space? Well, of course it is, in the broadest sense: a space of knowledge. Does it belong to an epistemic community or to more than one? Both answers are true. It belongs to one very diverse community of knowledge-epidemiologists around the globe. And to a lesser but no less impor tant extent, the dictionary pertains also to the many communities of knowledge that interact and cooperate with epidemiology, or with which epidemiology cooperates, or that simply use epidemiological reasoning, knowledge, methods, or techniques. No matter how many mistakes we may have made(eventually, they are all m responsibility), I would like to think that in making this new edition we again practiced a high level of scientific and intellectual rigor in two opposite and omplementary directions: (1) in selecting and defining terms that are at the ontological, epistemological, and methodological core of epidemiology, and (2)in selecting and defining terms that are near or within disciplines with which epidemiology maintains vital interactions-vital for epidemiology, the other disciplines, science, and society These I take to be facts: today research methods with strong epidemiological roots and properties are fruitfully applied"within"and"outside"epidemiology A positive blurring of the boundaries of epidemiological research methods occurred in the last decades of the last century: e. g, the integration of population thinking and group comparison into clinical and public health research. 10 The expansion of this influence toward other research areas remains a significant-and in my view highly attractive-challenge for many scientists. Such an expansion of influence will not be identical to what occurred via clinical epidemiology and, later, evidence-based medicine and, today evidence-based health care The nature of the hypotheses at stake is often quite different in clinical medicine
and currently work or have professional experience as an epidemiologist [you may also have professional experience in other fi elds],” 27% answered “While my main job is not as an epidemiologist, I often use epidemiologic knowledge, methods or reasoning in my work,” 2% selected “I have little to no training in epidemiology and I seldom or never use it in my work [your contribution is nevertheless welcomed],” and 4% “Other.” These data provide a factual background for the next paragraphs. Is this dictionary an attempt to demarcate epidemiology neatly? I don’t think so. Or I’d rather think it is not, to the extent that a dictionary can—or needs to—avoid demarcating a discipline.4 Yet like many other scientists, every now and then epidemiologists engage in boundary-making endeavors and disciplinary demarcation. And then, as usual in other disciplines, epidemiologists assert or reclaim contested epistemic authority and may claim jurisdiction over areas of public health, medicine, statistics, or science. These efforts evolved in the course of the twentieth century while epidemiology developed as a very diverse, eclectic— and foremost, integrative—fi eld of practice and academic discipline.4–12 And so will they evolve as the societies of the twenty-fi rst century continue developing. There is nothing wrong with that, it is the natural thing. Is this dictionary an epistemic space? Well, of course it is, in the broadest sense: a space of knowledge. Does it belong to an epistemic community or to more than one? Both answers are true. It belongs to one very diverse community of knowledge—epidemiologists around the globe. And to a lesser but no less important extent, the dictionary pertains also to the many communities of knowledge that interact and cooperate with epidemiology, or with which epidemiology cooperates, or that simply use epidemiological reasoning, knowledge, methods, or techniques. No matter how many mistakes we may have made (eventually, they are all my responsibility), I would like to think that in making this new edition we again practiced a high level of scientifi c and intellectual rigor in two opposite and complementary directions: (1) in selecting and defi ning terms that are at the ontological, epistemological, and methodological core of epidemiology, and (2) in selecting and defi ning terms that are near or within disciplines with which epidemiology maintains vital interactions—vital for epidemiology, the other disciplines, science, and society. These I take to be facts: today research methods with strong epidemiological roots and properties are fruitfully applied “within” and “outside” epidemiology. A positive blurring of the boundaries of epidemiological research methods occurred in the last decades of the last century; e.g., the integration of population thinking and group comparison into clinical and public health research.10 The expansion of this infl uence toward other research areas remains a signifi cant—and in my view highly attractive—challenge for many scientists. Such an expansion of infl uence will not be identical to what occurred via clinical epidemiology and, later, evidence-based medicine and, today, evidence-based health care. The nature of the hypotheses at stake is often quite different in clinical medicine xi Preface
Preface than in, say, molecular biology or proteomics. Largely because of this ontological fact, because biotechnologies generate and drive different types and amounts of information and research, and for other reasons, today epidemiological thinking continues to create new approaches, research designs, strategies of analysis, and causality for such biological disciplines. Thus the influence of epidemiology continues. The potential to improve the health of citizens is there. In fact, the rationale for task (2) mentioned above also includes the relevance of epidemiological methods for research on the public health problems that are best tackled by blending the reasoning and the tools of epidemiology and of some of the social sciences. Therefore, this new edition aims at being useful not only to classic epidemiological and clinical research, but would also like to continue favoring the integration of epidemiology into"microbiological"and "macrosocial"health research and practice. I am confident and content that much of this is already happening, and thus feel this book is rather in harmony ith most of the contemporary scientific world: wide open and interconnected- much more creative, relevant, efficient, and interesting because of the porousness and plasticity of the disciplines than because of the putative higher mission or language of their leaders and disciples. In short, if you live in a foreign land and have come to visit this book from "outside "epidemiology, be welcome. If you are an epidemiologist on the eve of atrip"to a foreign discipline, please take this book with you. And, again, if you mostly work"inside"epidemiology, please keep it at hand: this is your territory- yet I hope you will here discover new landscapes of unsuspected beauty. January 2008 barcelona
than in, say, molecular biology or proteomics. Largely because of this ontological fact, because biotechnologies generate and drive different types and amounts of information and research, and for other reasons, today epidemiological thinking continues to create new approaches, research designs, strategies of analysis, and ways to assess causality for such biological disciplines. Thus the infl uence of epidemiology continues. The potential to improve the health of citizens is there. In fact, the rationale for task (2) mentioned above also includes the relevance of epidemiological methods for research on the public health problems that are best tackled by blending the reasoning and the tools of epidemiology and of some of the social sciences. Therefore, this new edition aims at being useful not only to classic epidemiological and clinical research, but would also like to continue favoring the integration of epidemiology into “microbiological” and “macrosocial” health research and practice. I am confi dent and content that much of this is already happening, and thus feel this book is rather in harmony with most of the contemporary scientifi c world: wide open and interconnected— much more creative, relevant, effi cient, and interesting because of the porousness and plasticity of the disciplines than because of the putative higher mission or language of their leaders and disciples. In short, if you live in a foreign land and have come to visit this book from “outside” epidemiology, be welcome. If you are an epidemiologist on the eve of a “trip” to a foreign discipline, please take this book with you. And, again, if you mostly work “inside” epidemiology, please keep it at hand: this is your territory— yet I hope you will here discover new landscapes of unsuspected beauty. Miquel Porta January 2008 Barcelona Preface xii
Preface to the fourth edition 2001 DICTIONARY-MAKING. LIKE PAINTING THE SYDNEY HARBOUR BRIDGE, NEVER ENDS. As soon as an edition goes into production, I open a file for amendments to be made in the next one Formal preparation of this edition began in April 1999, when I distributed by e-mail and airmail a list of proposed items to about 80 correspondents around the world. I sent an expanded list to more than 100 correspondents in June 1999, and in August 1999 I sent more items and questions to about 130 correspondents. Finally, in January 2000, I asked a small group-Janet Byron Anderson, Iain Chalmers, Gary Friedman, Sander Greenland, Susan Harris, Ian McDowell, Miquel Porta, Bob Spasoff, Mervyn Susser, Michel Thuriaux, and Don Wigle--to review the new and revised old entries. The entire process is as open and iterative as practical realities allow. The wording of many definitions has been refined in light of repeated discussions with many participants. This edition tains the fruits of these labors-amounting to more than 150 new items nd about as many revisions of existing entries. There are more citations and statements about the provenance of terminology than in previous editions and several new illustrations. A few items previously included and several illustrations have been dropped. There are some notes for users. The acronyms have been integrated into the text. As in previous editions, flexibility in the use of technical terms is implied, although preferred usage is suggested by placement of detailed entries. The guiding principle has been to create a dictionary that is authoritative but not authoritarian. The improvements in this revision reflect the help of all those named here and others not named. All the shortcomings are mine John m. last Ottawa, May 2000
Dictionary-making, like painting the Sydney Harbour Bridge, never ends. As soon as an edition goes into production, I open a fi le for amendments to be made in the next one. Formal preparation of this edition began in April 1999, when I distributed by e-mail and airmail a list of proposed items to about 80 correspondents around the world. I sent an expanded list to more than 100 correspondents in June 1999, and in August 1999 I sent more items and questions to about 130 correspondents. Finally, in January 2000, I asked a small group—Janet Byron Anderson, Iain Chalmers, Gary Friedman, Sander Greenland, Susan Harris, Ian McDowell, Miquel Porta, Bob Spasoff, Mervyn Susser, Michel Thuriaux, and Don Wigle—to review the new and revised old entries. The entire process is as open and iterative as practical realities allow. The wording of many defi nitions has been refi ned in light of repeated discussions with many participants. This edition contains the fruits of these labors—amounting to more than 150 new items and about as many revisions of existing entries. There are more citations and statements about the provenance of terminology than in previous editions and several new illustrations. A few items previously included and several illustrations have been dropped. There are some notes for users. The acronyms have been integrated into the text. As in previous editions, fl exibility in the use of technical terms is implied, although preferred usage is suggested by placement of detailed entries. The guiding principle has been to create a dictionary that is authoritative but not authoritarian. The improvements in this revision refl ect the help of all those named here and others not named. All the shortcomings are mine. John M. Last Ottawa, May 2000 Preface to the Fourth Edition, 2001 xiii
