Demographic Projection Techniques for Regions and Smaller Areas: A Primer

129 Pages·2002·6.22 MB·English

by  H. Davis

Demographic Projection Techniques
for Regions and Smaller Areas
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H. Craig Davis
Demographic
Projection Techniques for
Regions and Smaller Areas:
A Primer
UBCPress /Vancouver
© UBC Press 1995
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, without prior written permission of
the publisher.
Printed in Canada on acid-free paper °o
ISBN 0-7748-0501-3
Canadian Cataloguing in Publication Data
Davis, H. Craig
Demographic projection techniques for regions and smaller areas
Includes bibliographical references and index.
ISBN 0-7748-0501-3
1. Population forecasting-Methodology. 2. Demography-Methodology. I. Title.
HB849.53.D38 1994 304.6'01'12 C94-910879-0
UBC Press gratefully acknowledges the ongoing support to its publishing program from
the Canada Council, the Province of British Columbia Cultural Services Branch, and the
Department of Communications of the Government of Canada.
UBC Press
University of British Columbia
6344 Memorial Road
Vancouver, BC V6T 1Z2
[phone]
Fax: [phone]
To the memory of my father,
Harrell Ross Davis
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Contents
Preface / xi
1 Introduction / 3
The Value of Population Projections / 3
Projections, Forecasts, and Estimates: Definitions / 5
The Basic Demographic Equation / 6
Overview of the Book / 7
2 Mathematical Extrapolation 1/8
The Linear Function 710
A Numerical Illustration 711
The Exponential Function 713
Linear Transformation of the Exponential Function 715
A Numerical Illustration 715
vii
viii Contents
Polynomial Functions 717
Linear Transformation of a Polynomial Function 717
A Numerical Illustration 718
The Hyperbolic Function 719
Linear Transformation of the Hyperbolic Function 719
A Numerical Example 7 20
Summary / 22
3 Mathematical Extrapolation II/24
The Modified Exponential Function / 24
Linear Transformation of the Modified Exponential Function / 26
A Numerical Illustration / 26
Mathematical Extrapolation: A Review / 27
Choosing among Extrapolations / 29
Measuring the Prediction Error / 30
A Four-Step Projection Procedure /31
Summary / 34
4 Comparative Methods / 35
Ratio Methods / 36
Constant Share Method / 37
Projected Share Methods / 37
Difference Methods / 39
Constant Difference Method / 39
Projected Difference Method / 39
Choosing among Methods / 40
Summary / 42
Contents ix
5 The Cohort-Survival Population Model / 44
The Basic Cohort Model / 45
A Numerical Illustration / 45
An Algebraic Summary / 47
Mortality / 48
Basic Measures / 48
Projecting Death Rates / 50
Fertility / 53
Basic Measures / 53
Projecting Birth Rates / 56
Summary / 58
6 Migration Models / 60
Basic Concepts /61
Immigration and Emigration /61
In-Migration and Out-Migration /61
Gross and Net Migration / 62
Causes of Migration / 63
Estimating Past Migration / 66
Direct Estimation of Migration / 66
Indirect Estimation of Migration / 67
Projecting Future Migration / 68
Extrapolation of Past Trends / 69
Regression Models / 72
Summary / 75
7 A Final Note / 77
Mathematical Extrapolation / 77