Demography of Tropical Africa 9781400877140

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THE D E M O G R A P H Y OF T R O P I C A L A F R I C A

UNDER THE EDITORIAL SPONSORSHIP OF THE OFFICE OF POPULATION RESEARCH PRINCETON UNIVERSITY

THE D E M O G R A P H Y

OF

TROPICAL AFRICA W I L L I A M BRASS, A N S L E Y J . COALE, P A U L D E M E N Y , DON F. H E I S E L , FRANK LORIMER, ANATOLE

ROMANIUK,

AND E T I E N N E V A N DE W A L L E

Copyright © 1968 by Princeton University Press ALL RIGHTS RESERVED

L. C. Card 67-21018 Printed in the United States of America by Princeton University Press

Preface This book weaves together strands of interest in African demography on the part of many persons and several institutions—strands that in some instances extend back for many years. The Office of Population Research has a tradition that began with its founding in 1936 of special attention to international demography, consistently emphasizing popu­ lation trends in the less developed areas of the world and the significance of these trends. Another persistent theme in the Office's research in­ terests has been the development and application of techniques of esti­ mation of such important variables as birth rates and death rates from the incomplete or inaccurate data that exist in these areas. When cen­ suses and special surveys providing quantitative information about a substantial fraction of the population of tropical Africa began to appear for the first time in the years after World War II, there was a natural interest at Princeton in seeing what could be learned from a systematic analysis of these data. In 1958 Karol J. Krotki, who as Census Con­ troller in the Sudan had played a major part in the planning and execu­ tion of the sample census of population in that country in 1956, com­ pleted a doctoral dissertation at Princeton entitled Estimating Vital Rates from Peculiar and Inadequate Age Distribution (Sudanese Ex­ perience). In the fall of 1960 Frank Lorimer accepted a part-time research posi­ tion at Princeton to conduct a reconnoitering survey of the extent and quality of population data on tropical Africa. Lorimer's active work on African population had begun in 1952 when he went on a mission for UNESCO that included making arrangements for field studies of fertility at the East African Institute of Social Research and at the University of Ghana. In 1957 he undertook a survey of existing infor­ mation on African population at Boston University in collaboration with members of the Africa Studies Program and published a report as a result of this survey entitled "Demographic Information on Tropical Africa." It was on Lorimer's initiative that the International Union for the Scientific Study of Population held a colloquium in Paris in 1959 which brought together demographers and statisticians who had a working knowledge of African population statistics. He also spent half a year at the University of Ghana in 1960 helping to inaugurate a program of population studies. As part of his exploratory work at the Office of Population Research in 1960-1962, Lorimer visited research centers and statistical offices in various African countries to complete the acquisition of basic data and related material. During 1961-1962 the Office decided to launch a full-scale research

PREFACE

program. William Brass and Don Heisel were added to the full-time professional staff for that year, and Paul Demeny devoted a substantial fraction of his research time to the project. Brass came to Princeton on leave of absence from Aberdeen University, where he was professor of statistics. Before assuming this post he had spent several years in the East African Statistical Office where he had had extensive first­ hand experience with population censuses, demographic surveys, and vital statistics. In Africa and in Aberdeen he had begun to invent and apply the methods of estimation that in a more developed form have been heavily utilized in this book and that indeed represent perhaps the most valuable single contribution of this project. The Director of the Office had, since the early 1940's, studied age patterns of mortality and their use in the construction of model life tables, and the use of age distributions in conjunction with model life tables to estimate the fertility and mortality of a population. In collaboration with Paul Demeny, he developed four families of "regional" model life tables and stable populations that form another principal basis of estimation used in this project, in addition to the techniques of Brass. Don Heisel had been trained in statistics and in techniques of demographic analysis at the University of Wisconsin. Anatole Romaniuk and Etienne van de Walle came to Princeton in the fall of 1960 as visiting students in the special training program at the Office of Popu­ lation Research. Romaniuk had a background of extensive experience and responsibility in a demographic survey of the Congo in 1956-1957 and van de Walle had been employed for four years by the Institut pour la Recherche Scientifique en Afrique Centrale in Ruanda-Urundi. During their year as visiting students both participated in the research project in addition to taking part in graduate seminars, and in the summer of 1962 they joined the project on a full-time basis. Most of the substantive analysis of demographic data from Africa was carried out by Brass, Demeny, Heisel, Lorimer, Romaniuk, and van de Walle. Coale contributed to the development of methods and constructed esti­ mates for some of the regions for which an intensive case study was not attempted. It was Frank Lorimer's wide personal knowledge of African statistics and of knowledgeable statisticians that made it possible to assemble this group, and it was his energy and enthusiasm that sup­ plied the impetus needed to launch the project. His advice and ideas contributed to almost every chapter, not merely those where he is listed as an author. An indispensable contributor to the completion of this volume was Marion O'Connor, who collected the data and made the calculations underlying the density map, made or supervised many of the computations throughout the volume, and patiently attempted to impose more consistency and uniformity on material prepared by dif-

PREFACE

ferent authors who often employed different statistical techniques. Mrs. O'Connor made a number of the estimates for territories that had not been the subject of intensive case studies and had a hand in drafting parts of the summary chapters. She assisted Lorimer in the collection of data and was responsible for putting and keeping the large body of statistical material amassed by the project in order. Remy Clairin spent three months on leave from the Institut National de la Statistique et des Etudes Economiques at Princeton and provided valuable first-hand knowledge and able technical assistance to William Brass in his case studies of areas where statistical inquiries had been made with INSEE assistance. Andrews Aryee, then with the Central Bureau of Statistics in Ghana, and Father Joseph Boute were also visiting students in the special training program in demography at Princeton during the period when this research was conducted and contributed from their special knowledge and experience. Hazel Chafey, who was secretary to the staff of the project, success­ fully handled an unusually difficult typing job. Most of the charts were drawn by Lynn Demeny, and the others by Joan Westoff. We cannot mention all of the persons who have given advice or statistical material to the project, but wish to acknowledge the generosity of the Statistical Offices of many countries in tropical Africa for providing us with special material often unpublished. Special acknowledgement is due Mr. Robert Blanc at INSEE for giving free access to the data compiled at his organization, and to Mr. John Blacker and Mr. A. T. Brough, respectively former demographer and chief statistician of the Ministry of Economic Development and Planning of Kenya for making available unpublished material from the sample census of Kenya in 1962. This project enjoyed financial support of special grants from The Population Council, largely from funds originating in the Carnegie Corporation. In addition, this project as well as other work at the Office of Popula­ tion Research was sustained by general support provided by the Rocke­ feller Foundation, the Ford Foundation, and the Milbank Memorial Fund. The computer facilities of Princeton University by which some of the tables were calculated are supported in part by the National Science Foundation (NSF-GP579). The editor of Population Studies generously gave permission to reproduce material that had been published in that journal. Ansley J. Coale

The Authors All of the authors were members of the professional staff at the Office of Population Research, Princeton Uni­ versity, when the manuscript was written. Their more recent affiliations are as follows: WILLIAM BRASS

Reader in Medical Demography, London School of Hygiene and Tropical Medicine. ANSLEY J. COALE

Director, Office of Population Research, Princeton Uni­ versity. PAUL DEMENY

Associate Professor of Economics, and Research As­ sociate at Population Studies Center, University of Michigan. DON F. HEISEL

Field Associate, The Population Council, Inc., at the University College, Nairobi. FRANK LORIMER

Visiting Professor of Demography, University of the Philippines. ANATOLE ROMANIUK

Associate Professor of Demography, Department of Social Sciences, University of Ottawa. ETIENNE VAN DE WALLE

Research Demographer, Office of Population Research, Princeton University.

Contents Preface

ν

List of Tables

xi

List of Figures

xxv

PART I. FERTILITY, MORTALITY, AND NUPTIALITY IN TROPICAL AFRICA: DATA, METHODS OF ANALYSIS, AND SUMMARY OF ESTIMATES CHAPTER 1. Introduction BY FRANK LORIMER

3

CHAPTER 2. Characteristics of African Demographic Data BY ΕΤΙΕΝΝΕ VAN DE WALLE

12

CHAPTER 3. Methods of Analysis and Estimation BY WILLIAM BRASS AND ANSLEY J. COALE

88

Appendix A: Note on Brass Method of Fertility Estimation

140

BY WILLIAM BRASS

Appendix B: Note on the Efiect of Age Misreporting

143

BY ETIENNE VAN DE WALLE CHAPTER 4. Summary of Estimates of Fertility and Mortality BY ANSLEY J. COALE AND FRANK LORIMER

Appendix: Notes on Areas for which Estimates Were Made but not Subject to a Detailed Study

151

168

BY ANSLEY J. COALE AND ETIENNE VAN DE WALLE CHAPTER 5. Marriage in African Censuses and Inquiries BY ETIENNE VAN DE WALLE

183

CONTENTS

PART II: CASE STUDIES OF THE DEMOGRAPHY OF AREAS COVERED BY PARTICULAR KINDS OF CENSUSES OR SURVEYS CHAPTER 6. The Demography of the Democratic Republic

of the Congo

241

BY ANATOLE ROMANIUK

Appendix: Schedules 1 and 2 used in Demographic Inquiry

340

CHAPTER 7. The Demography of French-Speaking Territories

Covered by Special Sample Inquiries: Upper Volta, Dahomey, Guinea, North Cameroon, and Other Areas

342

BY WILLIAM BRASS CHAPTER 8. The Demography of the Portuguese Territories:

Angola, Mozambique, and Portuguese Guinea

440

BY DON F. HEISEL

Appendix: The Tabulation of Age in the 1940 Census of Mozambique

462

CHAPTER 9. The Demography of the Sudan: An Analysis of the 1955/56 Census

466

BY PAUL DEMENY CHAPTER 10. Fertility in Nigeria BY ETIENNE VAN DE WALLE

515

Published Statistical Sources Used in this Volume

528

Index

533

χ

List of Tables Table 1.1

Table 1.2

Table 2.1 Table 2.2

Table 2.3 Table 2.4 Table 2.5 Table 2.6 Table 2.7

Table 2.8 Table 2.9 Table 2.10 Table 2.11 Table 2.12 Table 2.13 Table 2.14 Table 2.15

Table 2.16

Estimated 1960 population of countries in tropical Africa, and nature of data supporting fertility or mortality esti­ mates Coverage of population data from censuses and surveys after 1950 permitting the estimation of fertility and mor­ tality in tropical Africa Classification of females into "physiological" age inter­ vals—selected censuses and surveys Age distribution into broad age groupings (both sexes)— East African censuses and sample censuses in special areas Male percent age distribution—selected regions of Africa Female percent age distribution—selected regions of Africa Cumulated male percent age distribution—selected re­ gions of Africa Cumulated female percent age distribution—selected re­ gions of Africa Number of cases of age ratios above unity, and per­ centage of the total number of observations, by age and sex—INSEE inquiries and censuses of the Portuguese and English traditions Sex ratio of population—selected regions of Africa Sex ratios under or equal to unity at birth, under 1 year, and between age 1 and 4—selected regions of Africa Average parity, and percent distribution of women aged 40 and over by number of children—Guinea 1954-55 Age-specific fertility rates of women—selected regions of Africa Parity by age of mother—selected regions of Africa Ratios of parity to current fertility (P/F)—selected re­ gions of Africa Sex ratios of children ever born, by age of mother—se­ lected regions of Africa Correlations between proportions of women with zero children and with one and two children, and between proportions with one child and with two children—se­ lected regions of Africa Correlations between proportions of women with seven or more children and with zero, one, or two children— selected regions of Africa

14

16 17 21 25 29

35 39 44 50 53 54 62 63

65

LIST OF TABLES

Table 2.17 Table 2.18

Table 2.19 Table 2.20

Table 2.21 Table 2.22

Table 2.23 Table 3.1

Table 3.2

Table 3.3 Table 3.4 Table 3.5 Table 3.6

Table 3.7 Table 3.8 Table 3.9 Table 3.10

Percent childless women by age—selected regions of Africa Ratio of reported indices of fertility and of the propor­ tion females aged 15-44 to corresponding indices in a stable population—selected regions of Africa Age-specific death rates by sex—selected regions of Afri­ ca Infant mortality measures, (A) deaths under 1 year to 1,000 births of the year; (B) difference between births of year and children under 1, per 1,000 births; (C) dead children per 1,000 born during year; (D) proportion dead children per 1,000 children born to women aged 15-19 Proportion dead of children ever born—selected regions of Africa Correlation coefficient, by age of mother, of parity with proportion of children surviving—selected regions of Africa Ratio of mortality of children born during the last 12 months to infant mortality—selected French inquiries Multiplying factors for estimating the average value over five-year age groups of cumulated fertility (Fi) according to the formula Fi = φι + kifi (when U is for ages 14.5 to 19.5, 19.5 to 24.5, etc.) Comparison of estimated average cumulative fertility (F) and constructed numbers of children ever born per woman (P) Examples of P / F ratios computed from African census records Example to illustrate the P / F ratio method of estimating the level of fertility Illustration of the effect of age errors on P / F ratios Multiplying factors for estimating the proportion of chil­ dren born alive who die by age a, q(a), from the pro­ portion dead among children ever born to women 15-20, 20-25, etc. q ( a ) in four West model life tables as multiple of q s ( a ) q(a) in four South model life tables as multiple of qa(a) Comparison of multiplying factors derived from standard (S) and African (A) mortality patterns Values of a and β in logit p(a) = a + β logit ps(a) for North, South, East, and West model life tables (fe­ male), various levels of e°0, life table with e°0 = 50 serving as ps(a)

72 75

80 81

85 85

94

96 97 98 101

108 112

113 114

LIST OF TABLES

Table 3.11

Proportion surviving, p s { a ) , and corresponding logits at specified ages of the African standard life table Table 3.A.1 Model age-specific fertility rates, five-year age groups Table 3.A.2 Multiplying factors for estimating the average value over five-year age groups of cumulated fertility (F1) accord­ ing to the formula Fi = φι + kifi (when fo is for ages 15-20, 20-25, etc.) Table 3.B.1 Age distribution of recorded and stable population of the Congo Table 3.B.2 Distribution in recorded age classes of women belonging to given age classes of the stable population; age-specific fertility and number of births in the stable population Table 3.B.3 Comparison between the recorded and the stable popula­ tion Table 3.B.4 Age-specific fertility rates of the stable population and of the recorded population under three hypotheses con­ cerning the fertility of the transferred women Table 3.B.5 Cumulated fertilities with original age-specific fertility and under hypotheses 1, 2, and 3 Table 3.B.6 Parity of stable population and of recorded population under three hypotheses concerning the parity of the transferred women Table 3.B.7 P / F ratios under a combination of hypotheses concerning the fertility and the parity of the transferred women Table 4.1 Population, area, and density of countries in tropical Afri­ ca according to censuses or surveys since 1950 Table 4.2 Summary results of estimated fertility and mortality in tropical Africa Table 5.1 Data used in this study of marital status, by country and region, year of inquiry, and size of sample Table 5.2 Percent of adults in free unions, by sex—regions of Guin­ ea Table 5.3 Percent of persons 15 years or over, married and in free unions, by sex—Ivory Coast centers Table 5.4 Marital status in regions of Africa, for age groups 20-44 and 45 and over, by sex Table 5.5 Proportion single in regions of Africa by age and sex Table 5.6 Reported age distribution and reported percentage ever married, females 10-24—Guinea Table 5.7 Singulate mean age at marriage and age at first marriage in the stable population, by sex—regions of Africa Table 5.8 Proportion widowed, by age and sex, in percent of each age—regions of Africa

133 141

142 144

145 146

147 148

149 149 154 157 185 188 188 198 201 203 205 207

LIST OF TABLES

Table 5.9 Table 5.10 Table 5.11

Table 5.12 Table 5.13 Table 5.14 Table 5.15 Table 5.16 Table 5.17

Table 5.18

Table 5.19

Table 5.20

Table 5.21

Table 5.22

Table 5.23 Table 5.24 Table 5.25 Table 5.26

Proportion divorced, by age and sex, in percent of each age—regions of Africa Proportion of widows and inherited widows by age— Guinea Percentage of spouses in monogamous marriage, monoga­ mous consensual union, and polygynous union, by sex and age—the Congo Consensual unions in percent of all monogamous unions, by age and sex—provinces of the Congo Measures of polygyny—African regions Measures of polygyny—Congo provinces Percentage of married persons in polygynous unions, by sex and age—the Congo Percentage distribution of married persons by number of spouses, by sex and age—Guinea Numbers of married men and of married women in a hypothetical stable population (assuming equal numbers of males and females at each age) subject to Guinea's male and female nuptiality Polygyny, difference in singulate mean age of marriage between the sexes, and percentage divorced and widowed among women aged 45 and over—regions of Africa Polygyny, difference in mean age at marriage, in stable population, between the sexes, and percentage divorced and widowed among women aged 45 and over—provinces of the Congo Estimate of the deficit of wives living in the villages, de­ rived from the number of wives of specified order and im­ plied from the degree of polygyny of the husbands— Dakar and Abidjan Number of monogamously married wives per 100 monog­ amous husbands, by province and by type of settlement —the Congo Crude and standardized proportions males and females aged 20 and over who are in conjugal unions, by prov­ ince and by type of settlement—provinces of the Congo Percentage of monogamous unions that are consensual, by type of settlement—provinces of the Congo Polygynists per 100 married males, by type of settlement: crude and standardized proportions—the Congo Polygynists per 100 married males, by type of settle­ ment: crude and standardized proportions—Guinea Age-specific fertility rates per thousand women, by con­ jugal status—the Congo

211

211 213 214 215 216 211

21S

22C

22(

22:

22:

22' 22'

22( 22(

LIST OF TABLES

Table 5.27

Table 5.28 Table 5.29

Table 5.30 Table 5.31 Table 5.32 Table 6.1 Table 6.2

Table 6.3

Table 6.4 Table 6.5

Table 6.6 Table 6.7 Table 6.8

Table 6.9 Table 6.10 Table 6.11 Table 6.12 Table 6.13

"Illegitimate" fertility rates per thousand women aged 15-19, and minimal and maximal values among districts —provinces of the Congo Age-specific fertility rates per thousand wives, according to number of wives of the husband—Guinea Comparison of age-specific fertility rates: (A) women in consensual unions and in formal marriages; (B) wives of polygynists and of monogamists—the Congo Children ever born to women above age 50, according to total number of marriages ever contracted—Guinea Percentages of women childless, by age and by number of marriages—Fouta-Toro Singulate mean age of females at marriage, total fertility per woman, and crude birth rate—regions of Africa Size of sample compared to the estimated population, by district and province—the Congo, de facto population Ratio of de jure estimates and administrative estimates (1956) to de facto estimates from the 1955-57 Demo­ graphic Inquiry in the Congo Number of registered births and deaths and percentage of the population subject to compulsory registration of vital events, by year—the Congo and provinces, 1953-58 Distribution of territories by relative values of inquiry de facto estimates (F) and administrative estimates (AS) Estimated de facto population according to 1955-57 in­ quiry—the Congo, provinces, districts, and type of settle­ ment Males: Age distribution per 100, Demographic Inquiry 1955-57—the Congo, provinces, and districts Females: Age distribution per 100, Demographic Inquiry 1955-57—the Congo, provinces, and districts Reported and stable proportions (percent) under 10, by sex and five-year age groups, for birth rate 42.7 and life expectancy at birth 38.5—the Congo Reported (R) and stable (S) age distributions in numbers and percent—the Congo Male stable age distribution—the Congo, provinces, and districts Female stable age distribution—the Congo, provinces, and districts Ratio of the reported (R) to stable (S) male age dis­ tribution—the Congo, provinces, and districts Ratio of reported (R) to stable (S) female age distribu­ tion—the Congo, provinces, and districts

229 231

232 232 233 234 245

249

250 252

254 259 260

261 263 264 265 266 267

LIST OF TABLES

Table 6.14 Table 6.15 Table 6.16

Table 6.17 Table 6.18

Table 6.19

Table 6.20 Table 6.21

Table 6.22

Table 6.23

Table 6.24

Table 6.25

Table 6.26

Table 6.27

Table 6.28

Table 6.29

Rural, mixed, and urban population by age—the Congo Percent urban, adult sex ratio, and proportions male and female aged 15-45—the Congo and migration districts Proportions of present residents (PR), absent residents (AR)5 and visitors (V) in the enumerated population, by sex and age—Katanga Province Absent residents per 100 of de facto population, by age, in specified areas Coefficients of correlation obtained between the R/S ra­ tios in each age group vs. mean age at first marriage and estimated birth rate Sex ratio by age according to the 1955-57 inquiry—the Congo (rural, mixed, and urban) and provinces and dis­ tricts Sex ratio at birth in various surveys Number of deaths (a) officially registered in 1956 and (b) estimated in the 1955-57 inquiry, the ratio of (a) to (b), and death rates according to the inquiry—the Congo, provinces, and districts Death rates (per 1,000 population) by age and sex—the Congo, rural, mixed, and urban populations; Kasai Prov­ ince; and the districts of Cataractes and Bas Congo com­ bined Proportions of children who have died among those ever born, by age of mother at time of survey (per 1,000)— the Congo, provinces, and districts Estimated probability of death before age a, q(a), de­ rived from reports by mothers—the Congo, provinces, and districts Proportions of children who have died among those ever born, by age of mother at time of survey—the Congo and provinces, by type of settlement Probability of death before age a, q(a), derived from reports by mothers—the Congo and provinces, by type of settlement Observed q { 5) and hypothetical ¢'(5) values on the basis of specified q (a) and alternative models—the Con­ go Observed q ( 5) and hypothetical