National Academies Press: OpenBook
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

BEYOND SIX BILLION

Forecasting the World's Population

Panel on Population Projections

John Bongaarts and Rodolfo A. Bulatao, Editors

Committee on Population

Commission on Behavioral and Social Sciences and Education

National Research Council

NATIONAL ACADEMY PRESS
Washington, D.C.

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

NATIONAL ACADEMY PRESS
2101 Constitution Ave., N.W. Washington, D.C. 20418

NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the panel responsible for the report were chosen for their special competences and with regard for appropriate balance.

This study was supported by grants to the National Academy of Sciences from the Andrew W. Mellon Foundation, the David and Lucile Packard Foundation, the Rockefeller Foundation, the United States Agency for International Development, and the William and Flora Hewlett Foundation. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the organizations or agencies that provided support for the project.

Suggested citation: National Research Council (2000) Beyond Six Billion: Forecasting the World's Population. Panel on Population Projections. John Bongaarts and Rodolfo A. Bulatao, eds. Committee on Population, Commission on Behavioral and Social Sciences and Education. Washington, D.C.: National Academy Press.

Library of Congress Cataloging-in-Publication Data

National Research Council (U.S.)

Beyond six billion : forecasting the world's population / Panel on Population Projections, Committee on Population, Commission on Behavioral and Social Sciences and Education, National Research Council; John Bongaarts and Rodolfo A. Bulatao, editors.

p. cm.

ISBN 0-309-06990-4 (hard)

1. Population forecasting. I. Title: Beyond 6 billion. II. Bongaarts, John, 1945- III. Bulatao, Rodolfo A., 1944- IV. Title.

HB849.53 .N385 2000

304.6′2′0112--dc21

00-009983

Additional copies of this report are available from

National Academy Press
, 2101 Constitution Avenue, N.W., Lockbox 285, Washington, D.C. 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu

Printed in the United States of America

Copyright 2000 by the National Academy of Sciences. All rights reserved.

Cover: Hands, copyright The Stock Market/Don Mason, 2000, and view of the earth from space, NASA.

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

THE NATIONAL ACADEMIES

National Academy of Sciences

National Academy of Engineering

Institute of Medicine

National Research Council

The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.

The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. William A. Wulf is president of the National Academy of Engineering.

The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine.

The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. William A. Wulf are chairman and vice chairman, respectively, of the National Research Council.

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
This page in the original is blank.
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

PANEL ON POPULATION PROJECTIONS

JOHN BONGAARTS (Chair),

The Population Council, New York City

JUHA M. ALHO,

Department of Statistics, University of Joensuu, Finland

ALAKA M. BASU,

Division of Nutritional Sciences, Cornell University

JOHN G. CLELAND,

Centre for Population Studies, London School of Hygiene and Tropical Medicine

JOEL E. COHEN,

Laboratory of Populations, Rockefeller University and Columbia University

KENNETH H. HILL,

Department of Population and Family Health Services, Johns Hopkins University

NICO KEILMAN,

Department of Economics, University of Oslo, Norway

RONALD D. LEE,

Department of Demography, University of California, Berkeley

MASSIMO LIVI-BACCI,

Department of Statistics, University of Florence, Italy

DOUGLAS S. MASSEY,

Department of Sociology, University of Pennsylvania

S. PHILIP MORGAN,

Department of Sociology, Duke University

ALBERTO PALLONI,

Department of Sociology, University of Wisconsin, Madison

ANNE R. PEBLEY,

School of Public Health and Department of Sociology, University of California, Los Angeles

SHARON STANTON RUSSELL,

Center for International Studies, Massachusetts Institute of Technology

WARREN C. SANDERSON,

Department of Economics, State University of New York, Stony Brook

THOMAS SCHELLING,

School of Public Affairs, University of Maryland, College Park

MICHAEL TEITELBAUM,

Alfred P. Sloan Foundation, New York City

JAMES W. VAUPEL,

Max Planck Institute for Demographic Research, Rostock, Germany

RODOLFO A. BULATAO, Study Director

HOLLY E. REED, Research Associate

ELIZABETH A. WALLACE, Project Assistant

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

COMMITTEE ON POPULATION

JANE MENKEN (Chair),

Institute of Behavioral Sciences, University of Colorado, Boulder

CAROLINE H. BLEDSOE,*

Department of Anthropology, Northwestern University

JOHN BONGAARTS,

The Population Council, New York City

ELLEN BRENNAN-GALVIN,

Population Division, United Nations, New York City

JOHN N. HOBCRAFT,

Population Investigation Committee, London School of Economics

F. THOMAS JUSTER,

Institute for Social Research, University of Michigan, Ann Arbor

CHARLES B. KEELY,

Department of Demography, Georgetown University

DAVID I. KERTZER,

Department of Anthropology, Brown University

DAVID A. LAM,

Population Studies Center, University of Michigan, Ann Arbor

LINDA G. MARTIN,*

The Population Council, New York City

MARK R. MONTGOMERY,*

The Population Council, New York City, and Department of Economics, State University of New York, Stony Brook

W. HENRY MOSLEY,

Department of Population and Family Health Sciences, Johns Hopkins University

ALBERTO PALLONI,

Center for Demography and Ecology, University of Wisconsin, Madison

JAMES P. SMITH, RAND,

Santa Monica, California

BETH J. SOLDO,*

Population Studies Center, University of Pennsylvania

JAMES W. VAUPEL,

Max Planck Institute for Demographic Research, Rostock, Germany

KENNETH W. WACHTER,

Department of Demography, University of California, Berkeley

LINDA J. WAITE,

Population Research Center, University of Chicago

BARNEY COHEN, Director

*Through October 1999.

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

Preface

Population projections are the demographic outputs most used by nondemographers and most neglected by population scientists. Nondemographers may be surprised at the lack of a rigorous theoretical or even historical basis for the scenarios underlying the most commonly used projections. The task of making world projections—assessing the plausibility of current demographic estimates and choosing appropriate assumptions about future trends—are left by default to the small projection staffs of the United Nations Population Division, the World Bank, the U.S. Census Bureau, and similar agencies. These staffs, while qualified to do so, have neither the time nor the resources to conduct new research or fully evaluate current scientific work on the whole range of assumptions that undergird projections.

The wider public may take notice when projections change, though they may not understand the reason. When the 1996 United Nations projections were released, the medium-variant projection for the year 2050 was smaller by 466 million persons than the projection for the same year made in 1994. This change was widely reported as evidence that population growth was not as big a problem as had been previously thought. In fact, the projected annual rate of growth had been changed only slightly. And both the earlier and the later projections had in any case quite wide and overlapping bands of uncertainty around them, as the producers of the projections understood, but most consumers may not have realized.

Recognizing the desirability of both more systematic research atten-

Page viii Cite
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

tion to population projections and better public understanding of them, the National Research Council's Committee on Population, at the request of several sponsors, convened a panel of experts in 1998 to look at projections in greater depth. The panel was asked to examine in detail the demographic assumptions, both explicit and implicit, that underlie world population projections. The panel was not asked to produce alternative projections but to firm up the scientific foundation for these continuing efforts through a thoughtful review of projection methods and assumptions and an assessment of recent research on fertility, mortality, and migration that has relevant implications. The panel was also asked to review existing population projections for accuracy and to recommend improvements where appropriate. Finally, the panel was asked to develop a research agenda that would direct attention to areas in which progress might be of benefit to projections.

The panel met five times over 18 months to review the relevant knowledge base and formulate its conclusions and recommendations. This report summarizes the panel's work, reflecting its deliberations and presenting its recommendations. We have introduced an innovation, where committee reports are concerned, in publishing this report. For reasons of convenience and cost, the printed volume contains the body of the report but not the supporting technical appendices. Instead, the appendices are available on the National Academy Press web site ( http://www.nap.edu) and can also be printed on demand, at cost.

This report represents the collaborative efforts of the members of the Panel on Population Projections, whose names appear at the front. We are grateful to them for their dedication and willingness to review material, prepare drafts, and deliberate long hours on fine points in the report. One deserves special recognition. We were extremely fortunate to have been able to enlist the services of John Bongaarts, who chaired the panel superbly, formulated and promoted a sound framework for the report, and devoted many hours attending to its progress.

The panel benefited from essential information, data, clarification, and advice provided by liaison representatives of the agencies that produce world projections: Joseph Chamie and Larry Heligman of the United Nations Population Division, Eduard R. Bos of the World Bank, Peter Way of the U.S. Census Bureau, and Wolfgang Lutz of the International Institute for Applied Systems Analysis. Census Bureau data were also provided by Patricia Rowe and Thomas McDevitt.

Background work on long-term fertility was commissioned from John C. Caldwell, Bamikale Feyisetan, Peng Xi Zhe, Ignez Helena Oliva Perpetuo, and Laura Lidia Rodriguez Wong. Assistance in statistical modeling was provided by Anne Ruuskanen at the University of Joensuu and

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

Gretchen Stockmayer at the University of California, Berkeley. Informal reviews of preliminary statistical work were provided by Michael Stoto and Hania Zlotnik.

The panel gratefully acknowledges financial support from several sponsors: the Andrew W. Mellon Foundation, the David and Lucile Packard Foundation, the Rockefeller Foundation, the William and Flora Hewlett Foundation, and the United States Agency for International Development. Partial support for statistical modeling was also provided through a grant from the Academy of Finland.

Finally, no project of this magnitude could be undertaken without a well-managed and able staff. In particular, the role of Randy Bulatao as the study director was especially important. He worked closely with panel members in drafting and revising all the chapters, planned the panel meetings and coordinated the interchange among panelists, and contributed an extensive and valuable new analysis of errors in past population projections. In addition, Holly Reed prepared an appendix on projection software, and Elizabeth Wallace organized the panel's various meetings and provided essential administrative support. Christine L. McShane skillfully edited the report and provided other valuable assistance in preparing it for publication.

This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the Report Review Committee of the National Research Council. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making the published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.

We thank the following individuals for their participation in the review of this report: Brian J.L. Berry, School of Social Science, University of Texas, Dallas; John C. Caldwell, National Centre for Epidemiology and Population Health, Australian National University, Canberra; Jean-Claude Chesnais, Institut National d'Etudes Démographiques, Paris; Henri Leridon, Institut National d'Etudes Démographiques, Paris; John Long, Population Division, U.S. Census Bureau; Geoffrey McNicoll, Population Council, New York, and Australian National University, Canberra; Samuel H. Preston, School of Arts and Sciences, University of Pennsylvania; Andrei Rogers, Institute of Behavioral Science, University of Colorado, Boulder; Michael Stoto, School of Public Health and Health Services, George Washington University; and Shripad Tuljapurkar, Mountain View Research, Inc., Los Altos, California.

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

Although the individuals listed above provided constructive comments and suggestions, it must be emphasized that responsibility for the final content of this report rests entirely with the authoring panel and the institution.

Jane Menken, Chair

Committee on Population

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

 3

 

TRANSITIONAL FERTILITY

 

53

   

 Fertility Change in Developing Regions,

 

53

   

 Reasons for Fertility Decline,

 

56

   

 Current Methods of Projecting Fertility,

 

63

   

 Fertility Transition in the 21st Century,

 

68

   

 Conclusions,

 

75

   

 References,

 

78

 4

 

POSTTRANSITION FERTILITY

 

83

   

 Fertility Levels and Past Trends,

 

84

   

 Projected Fertility Trends,

 

87

   

 Interpreting Fertility Trends,

 

91

   

 Explaining Fertility Trends,

 

97

   

 Possible Policy Responses,

 

101

   

 Future Technological Developments,

 

104

   

 Conclusions,

 

106

   

 References,

 

108

 5

 

MORTALITY

 

114

   

 Current Levels of Life Expectancy,

 

115

   

 Mortality Transition,

 

117

   

 Mortality Projections,

 

127

   

 Future Trends in Life Expectancy,

 

135

   

 Conclusions,

 

146

   

 References,

 

150

 6

 

INTERNATIONAL MIGRATION

 

156

   

 Current Levels and Trends,

 

157

   

 Future Migration Trends,

 

168

   

 Projecting Migration,

 

174

   

 Improving Migration Projections,

 

177

   

 Conclusions,

 

182

   

 References,

 

185

 7

 

THE UNCERTAINTY OF POPULATION FORECASTS

 

188

   

 The Scenario Approach and Its Problems,

 

190

   

 Thinking About Forecast Errors,

 

194

   

 Three Approaches to Constructing Predictive Distributions,

 

200

   

 New Estimates of Uncertainty Based on Ex Post Analysis,

 

206

   

 Conclusions,

 

214

   

 References,

 

216

 

 

BIOGRAPHICAL SKETCHES

 

218

Page xiii Cite
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

Tables and Figures

TABLES

 1-1

 

Population projections by four international agencies for the world and major regions,

 

21

 1-2

 

Population of the world's 10 largest countries, 1995 and 2050,

 

22

 1-3

 

Percent of population aged 65 and over for the world and major regions,

 

23

 3-1

 

Difference between projected total fertility and 1998 estimate,

 

66

 4-1

 

Low-fertility countries by region, their populations, and their shares of world population,

 

85

 4-2

 

Classification of countries by total fertility in 1950-1955 and 1990-1995,

 

89

 4-3

 

Change in average total fertility by birth order, and the amount of change due to tempo effects: Italy and the United States,

 

97

 5-1

 

Factors expected to affect life expectancy trends in developing countries,

 

140

 5-2

 

Number of cases of life expectancy decline in the period 1950-1995,

 

142

 6-1

 

Foreign-born population by world region, 1965-1990,

 

158

 6-2

 

Net migration per thousand by world region, 1985-1995,

 

161

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

 B-1

 

Error in projected population: Means across countries, by forecast and projection length,

 

260

 B-2

 

Error in projected population by target year,

 

262

 B-3

 

Alternative proportional-error measures adjusted for erroneous base estimates,

 

269

 B-4

 

Error in projected component rates,

 

270

 B-5

 

Error in net migration rate by target period,

 

273

 B-6

 

Analyses of covariance for absolute proportional error in projected population,

 

276

 B-7

 

Deviations from the grand mean for absolute percentage error in projected population,

 

278

 B-8

 

Deviations from the grand mean for absolute percentage error in base population,

 

280

 B-9

 

Regressions to account for proportional error in projected population,

 

281

 B-10

 

Summary of analysis of covariance for absolute error in projected component rates,

 

284

 B-11

 

Summary of analysis of variance for absolute error in base component rates,

 

285

 B-12

 

Adjusted deviations from mean absolute error in component rates,

 

286

 B-13

 

Proportional error in projected world population,

 

291

 B-14

 

Absolute proportional error in projected world population,

 

292

 C-1

 

Cases available for analysis of fertility transition,

 

305

 C-2

 

Means and standard deviations,

 

306

 C-3

 

Correlations between rates of fertility change by period,

 

308

 C-4

 

Regressions for change in total fertility between 5-year periods during midtransition,

 

310

 C-5

 

Regressions for change in total fertility between 5-year periods during pre- and early transition,

 

312

 C-6

 

Regressions for change in total fertility between 5-year periods during late transition,

 

313

 D-1

 

Selected population outcomes in simulated projections with varying gains in life expectancy,

 

317

 E-1

 

Mean error in migration projected in different ways,

 

320

 E-2

 

Mean absolute error in projected net migration rate,

 

321

 F-1

 

Regional classification used in estimating uncertainty,

 

334

 F-2

 

Estimates of within-region correlations of errors,

 

336

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

 F-3

 

Upper endpoints of 95-percent prediction intervals for relative error and multipliers to obtain the average regional scale,

 

339

 F-4

 

Ratio of the upper endpoint of the 95-percent prediction interval to the median world forecast,

 

342

 F-5

 

U.N. forecast for 2050 and ratios of upper and lower bounds to 50-year medium or median forecast,

 

343

 F-6

 

Quantiles of the predictive distribution for world population in 2010, 2030, and 2050,

 

344

 F-7

 

Quantiles of the predictive distribution for world population, adjusted for possible errors and possible interregional correlation,

 

346

FIGURES

 1-1

 

World population size: Historical estimates and alternative projections,

 

18

 1-2

 

World population growth rates and annual increments, 1950-2050,

 

20

 1-3

 

Percentage change in population between 2000 and 2050 in standard projections and change due to population momentum alone,

 

28

 2-1

 

U.N. forecasts of world population in the year 2000 and their percentage error,

 

39

 2-2

 

Mean bias and mean absolute error in country population projections for the year 2000,

 

40

 2-3

 

Mean absolute error in country population projections,

 

43

 2-4

 

Mean percentage error by age group and projection length: Europe and Northern America combined,

 

46

 2-5

 

Mean percentage error by age group and projection length: Asia, Africa, and Latin America combined,

 

47

 2-6

 

Variance of the error in projected population accounted for by different factors,

 

49

 3-1

 

Percentage of countries that have started fertility decline by a given date,

 

54

 3-2

 

Estimated and projected total fertility rates by region: 1950-2050,

 

56

 3-3

 

Percentage of population literate in countries starting fertility transition,

 

62

 3-4

 

Trend in total fertility for developing regions and earlier projected trends, 1960-2000,

 

67

Page xvii Cite
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

 4-1

 

Past and projected total fertility in low-fertility countries, 1950-2050,

 

86

 4-2

 

Error in projected total fertility averaged across countries and forecasts,

 

91

 4-3

 

Observed total fertility and total fertility adjusted for the tempo effect: Italy and the United States, 1950-1995,

 

95

 5-1

 

Estimated and projected life expectancy by region, 1950-2050,

 

116

 5-2

 

Age patterns of female mortality and life expectancies, Sweden, 1900-1996,

 

116

 5-3

 

Percentage declines in mortality among females by age, Sweden, 1900-1996,

 

121

 5-4

 

Historical trends in life expectancy, England and Wales and Sweden, 1540-1996,

 

123

 5-5

 

Mean annual gains in life expectancy for industrial countries and three groups of developing countries, 1955-1995,

 

126

 5-6

 

Currently estimated trend in world life expectancy and various projections,

 

131

 5-7

 

Mean error in projected life expectancy, across countries and forecasts,

 

132

 5-8

 

Observed U.S. life expectancies and various projections by the U.S. Social Security Administration, 1930-2030,

 

134

 5-9

 

Impact of HIV/AIDS: Estimated and projected life expectancy in South Africa and Zimbabwe,

 

144

 6-1

 

Percentage of regional populations who are migrants, and regional shares of world migrant stock, 1990,

 

160

 6-2

 

Net migration rate, 1990-1995, by percentage of labor force in agriculture,

 

168

 6-3

 

Natural increase and net migration rate per thousand by region, 1990-1995,

 

173

 6-4

 

Absolute error from projecting net migration rate as zero, constant, or differentiated,

 

176

 7-1

 

Percentage of times the projected U.N. high-low interval encloses the actual subsequent population,

 

193

 7-2

 

Absolute proportional error in world and country projections, by projection length,

 

197

 7-3

 

Correlations between regional errors in projected population over the period 1970-1995,

 

199

 7-4

 

Four stochastic sample paths for industrial-region total fertility and 95-percent prediction interval,

 

205

Page xviii Cite
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

 7-5

 

Estimated 95-percent prediction interval for population projected 10 years: 13 large countries,

 

209

 7-6

 

Estimated 95-percent prediction interval for population projected 50 years: 13 large countries,

 

210

 7-7

 

Estimated 95-percent prediction interval for population projected 50 years: 10 regions and the world,

 

211

 7-8

 

Projected world population: U.N. projections and estimated 95-percent prediction interval,

 

213

 B-1

 

Proportional error and absolute proportional error,

 

263

 B-2

 

Proportional error by projection length: Percentiles for all countries,

 

264

 B-3

 

Population trends in five countries experiencing demographic quakes,

 

265

 B-4

 

Proportional error and absolute proportional error by the occurrence of demographic quakes,

 

266

 B-5

 

Proportional error by region,

 

267

 B-6

 

Absolute proportional error by region,

 

268

 B-7

 

Error in projected total fertility,

 

271

 B-8

 

Error in projected life expectancy,

 

272

 B-9

 

Error in projected net migration rate,

 

274

 B-10

 

Percent of variance in proportional error in projected population explained by proportional error in base population and error in component rates,

 

282

 B-11

 

Deviations from mean absolute error in projected and base total fertility,

 

288

 B-12

 

Deviations from mean absolute error in projected and base life expectancy,

 

289

 B-13

 

Deviations from mean absolute error in projected and base net migration rate,

 

290

 B-14

 

Mean country proportional error and world proportional error,

 

293

 B-15

 

Proportion of country error unoffset in world projections,

 

294

 B-16

 

World total fertility rate in various forecasts,

 

295

 B-17

 

World life expectancy in various forecasts,

 

297

 C-1

 

Five-year change in total fertility as a function of initial level,

 

307

 C-2

 

Simulated trends in midtransition total fertility,

 

311

 E-1

 

Net migrants and absolute error assuming constant net migrants, by country,

 

322

 E-2

 

Mean absolute error from projecting net migrants under zero, constant, or differentiated assumptions,

 

324

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×

BEYOND SIX BILLION

Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
This page in the original is blank.
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR1
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR2
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR3
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR4
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR5
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR6
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR7
Page viii Cite
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR8
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR9
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR10
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR11
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR12
Page xiii Cite
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR13
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR14
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR15
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR16
Page xvii Cite
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR17
Page xviii Cite
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR18
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR19
Suggested Citation:"Front Matter." National Research Council. 2000. Beyond Six Billion: Forecasting the World's Population. Washington, DC: The National Academies Press. doi: 10.17226/9828.
×
PageR20
Next: Executive Summary »
Beyond Six Billion: Forecasting the World's Population Get This Book
×

Is rapid world population growth actually coming to an end? As population growth and its consequences have become front-page issues, projections of slowing growth from such institutions as the United Nations and the World Bank have been called into question.

Beyond Six Billion asks what such projections really say, why they say it, whether they can be trusted, and whether they can be improved. The book includes analysis of how well past U.N. and World Bank projections have panned out, what errors have occurred, and why they have happened.

Focusing on fertility as one key to accurate projections, the committee examines the transition from high, constant fertility to low fertility levels and discusses whether developing countries will eventually attain the very low levels of births now observed in the industrialized world. Other keys to accurate projections, predictions of lengthening life span and of the impact of international migration on specific countries, are also explored in detail.

How good are our methods of population forecasting? How can we cope with the inevitable uncertainty? What population trends can we anticipate? Beyond Six Billion illuminates not only the forces that shape population growth but also the accuracy of the methods we use to quantify these forces and the uncertainty surrounding projections.

The Committee on Population was established by the National Academy of Sciences (NAS) in 1983 to bring the knowledge and methods of the population sciences to bear on major issues of science and public policy. The committee's work includes both basic studies of fertility, health and mortality, and migration; and applied studies aimed at improving programs for the public health and welfare in the United States and in developing countries. The committee also fosters communication among researchers in different disciplines and countries and policy makers in government, international agencies, and private organizations. The work of the committee is made possible by funding from several government agencies and private foundations.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!