Historical Demography
Zhongwei Zhao
Australian Demographic and Social Research Institute, Australian National University,
Australia
Keywords: historical demography, population history, demographic transition, fertility
decline, household formation, household composition, demographic data, historical data,
parish registers, genealogies, population registers, household registers, census, censustype materials, vital registration, aggregated population statistics, family reconstitution,
inverse projection, back projection, generalised inverse projection, computer simulation,
micro-simulation, Coale’s fertility indices
Contents
1. Historical Demography
2. The Development of Historical Demography
2.1. The Early Development of Historical Demography in France
2.2. The Cambridge Group and the Advancement of Historical Demography in England
2.3. The Historical Investigation of Fertility Transition in Europe
2.4. Historical Demography in East Asia
2.5. Historical Demography in Other Areas and Its Recent Development
3. Major Data Sources for Historical Demography
3.1. Parish Registers
3.2. Population Registers and Census-type Materials
3.3. Family or Lineage Genealogies
3.4. Other Data Sources
4. Methodological Development
4.1. Family Reconstitution
4.2. Inverse Projection, Back Projection, and Generalised Inverse Projection
4.3. Computer Simulation
4.4. Coale’s Fertility Indices and Other Methodological Developments
5. Concluding Remarks: Historical Demography at the Beginning of the Twenty-first
Century
Summary
Historical demography is an important component of demography. Its aim is to obtain
detailed information about population changes and people’s demographic behaviour in
the past through applying demographic methods to historical data. Since its establishment
as an academic discipline in the mid-twentieth century, historical demography has
advanced at a rapid pace and made significant contribution to the development of
demographic theories and to our understanding of population changes in both historical
and contemporary societies.
1
This chapter starts with the definition of historical demography, its relationship with
demography and demographic history, and main reasons why historical demography
established itself so rapidly in the 1950s. It then summarizes major developments in
historical demography in the past half century. Following that the primary data sources
available to historical demographers and some methodological developments made in
historical demography are discussed. The chapter concludes with comments on the likely
future challenges and opportunities for advancing historical demography in the world.
1. Historical Demography
Historical demography is commonly defined as the application of conventional and nonconventional demographic techniques to data sets from the past (Pressat and Wilson 1985;
Smith 2003). Its primary aim is to obtain detailed demographic information and measure
demographic changes such as changes in population size, age structure, sex ratio, fertility,
mortality, and migration for populations in the past. While estimating the total population
in a particular historical setting can be regarded as historical demography at its crudest
level, the application of demographic methods to historical source materials and the
information generated by such application can be far more elaborate.
Historical demography is closely related to, but differs from, demographic or population
history. The former concentrates largely on obtaining the detailed and accurate
demographic information for historical populations that provides the foundation for the
study of demographic or population history. The latter includes historical demography as
a field of enquiry, but covers wider research areas. Demographic history investigates not
only the process of past population changes, but also the interrelationship between these
changes and a wide range of socio-economic, political, cultural and environmental factors.
In general, historical demography tends be more involved in tackling the technical
problems of measuring past demographic changes and developing effective methods of
analysing historical population data, whereas demographic history is more concerned
with the reasons, processes and consequences of major demographic events, especially
their long-term impact on socio-economic changes and historical development.
Population changes interact closely with, and play a major part in, political, social and
economic changes. Through offering detailed and reliable demographic information
about past societies, historical demography can greatly improve our knowledge of history
and population history in particular. One of such examples is E. A. Wrigley and R. S.
Schofield’s monumental work The Population History of England 1541-1871 (1981).
This study, based on extensive empirical evidence and demographic estimates,
systematically examines population trends in England over a period of more three
hundred years and the population theory proposed by Thomas Robert Malthus (17661834). The comprehensive analysis presented in this book provides great insights into
demographic patterns and their interplay with socio-economic conditions in the time
before and during the industrial revolution. The impact of this work has been felt far
beyond the disciplinary confines of historical demography or population history.
2
While a distinction between historical demography and demographic history can be and
has been made by some scholars, it is difficult in practice to draw a clear line between the
two approaches and their practitioners. Demographic historians often need to have
detailed and accurate demographic information as the foundation for their investigation
into population history. Equally, historical demographers also want to examine socioeconomic reasons for population changes and the impact of such changes on the society.
Because of the close connection between the two disciplines, the discussion presented in
this chapter will not be confined within the area narrowly defined by historical
demography.
Historical demography is a major component of demography that studies population
changes, but it is primarily concerned with applying demographic methods to population
data from the past. Demographers wishing to test a proposed hypothesis on contemporary
population can, at least theoretically, always collect the data they need according to their
research design. Historical demographers, however, have to use existing data – they
cannot go back in time to collect the required data. The available data may not have been
collected for the purpose of demographic research; they may suffer from various types of
registration problems or biases that are often related to the rules or procedures applied in
creating the data. This makes historical demographic research a more challenging task
than the study of contemporary population issues. For this reason, historical
demographers often need to develop new techniques or modify conventional
demographic methods so that they can be effectively used in analysing surviving
historical data – a point that will be further discussed in section four of this chapter.
Historical demography has made a significant contribution to the development of
demography. Through enriching the knowledge about demographic behaviour and
population changes in the past, historical demography helps us to gain a better
understanding of demographic trends in contemporary societies and future. Louis Henry
(1911-1991), the founding father of historical demography, once suggested that, to
answer the two questions about population changes that intrigued demographers in the
mid-twentieth century, “Where are we?” and “Where are we headed?” we should begin
by answering a third, “Where were we yesterday and the day before?”. This reference to
the past is, he said, essential for it alone can tell us about the day after (Rosental 2003:
98). The importance of historical demography to the development of demography does
not stop here, however. After the Second World War, there was a considerable increase
in the interest in population issues throughout the world, and demography as an academic
discipline entered a period of rapid development. Mortality and fertility, which had
decreased notably in the nineteenth century and the first half of the twentieth century, fell
to low levels in most developed countries. These countries had well-established vital
registration systems and conducted regular censuses and population surveys. Population
data obtained through these modern-day efforts were, however, simply insufficient for
uncovering the process of demographic transition and people’s demographic behaviour in
the pre-transition society – both of which were of overriding importance to the
development of demographic theories and the understanding of population changes of the
time. Even in countries where detailed mortality and fertility data had been collected
during the process of their demographic transition, those available to researchers were
3
usually limited to published census or survey results. Public release of original census or
vital registration records was often prohibited for long periods after the records were
taken, whilst some countries destroyed the records altogether because of privacy concerns.
Such practices gave historical demography a unique opportunity to fill important gaps in
demographic research. As we shall see, the investigation of population changes in the
past has contributed to the development of many important and widely used population
theories, analytical models and demographic techniques.
2. The Development of Historical Demography
Although it is widely accepted that historical demography was established by the French
demographer L. Henry in the 1950s, interest in population history had existed long before
the twentieth century, and many researchers engaged in the study of past population
changes and made great contributions to the development of historical demography. As
early as the seventeenth century, John Graunt (1620-1674) already critically examined
available demographic data. His insightful analysis led to the publication of a landmark
study, Natural and Political Observations Made upon the Bills of Mortality in 1662,
which in many ways laid the foundation for the development of demography. Thomas
Robert Malthus also systematically examined demographic data available to him, and
published, between 1798 and 1826, six editions of his famous treatise, An Essay in the
Principle of Population. Malthus’s population theory, though very controversial, has
profoundly influenced the intellectual thinking, especially the development of population
thoughts, in the world over the last two hundred years. Many other pioneers, such as
William Petty (1623-1687), Gregory King (1648-1712), Johann Süssmilch (1707-1767);
Adolphe Quételet (1796-1874), and William Far (1807-1883) were also involved in the
study of population and in collecting and analysing demographic data between the
seventeenth and nineteenth centuries. Their works made direct contribution to historical
demography and population studies, and further enriched demographic theories
developed up to their time.
By the early twentieth century, interest in historical demography had grown significantly
enough for a Commission for Historical Demography to be formed in 1928 under the
auspices of the International Congress of Historical Sciences. The number of scholars
working on historical demography and related issues continued to increase. Some
researchers also started to explore the potential of using surviving parish records of births,
marriages, and burials in the study of population history. In the 1940s, for example,
Hannes Hyrenius, a Swedish demographer, analysed parish registers and applied methods
similar to those used by Henry a decade later. The impact of Hyrenius’ work was rather
limited, however, partly because it was published in Swedish, and appeared during the
Second World War (Rosental 2003). A great change took place after the war. Historical
demography established itself as an academic discipline in the 1950s and soon entered a
period of rapid development (Wrigley, 1981; Saito 1996).
2.1. The Early Development of Historical Demography in France
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Differing greatly from that predicted on the basis of the pre-war downward fertility trend,
a baby boom took place in many countries after the Second World War. This unexpected
change puzzled many demographers and the uncertainty surrounding the upsurge in
fertility also shook their confidence in correctly forecasting future population trends.
There was a further matter that had long concerned demographers and politicians in
France. In comparison with other European countries, fertility decline started much
earlier in France and its fertility had remained low for many decades. To explain such
fertility differentials and their recent changes, and to improve the ability of providing
reliable population forecast, there was an urgent need to get a better understanding of
people’s reproductive behaviour and related issues.
L. Henry, working at the Institut National d’Études Démographiques (INED), was one of
the researchers who were actively involved in pursuing these studies at the time. Henry
believed that, to identify the underlying causes of changes in reproductive behaviour and
fertility, demographers needed not only to obtain detailed information about marriage
patterns and marital fertility, but also to distinguish and measure controlled and
uncontrolled fertility. He defined an important theoretical concept: natural fertility.
According to him, deliberate birth control ‘can be said to exist when the behavior of the
couple is bound to the number of children already born and is modified when this number
reaches the maximum which the couple does not want to exceed.’ Natural fertility is
deemed to exist in the absence of such deliberate birth control (Henry 1961: 81).
Although the concept of natural fertility has certain limitations, (for example, it does not
consider the issue of non-parity related fertility control) it has been widely accepted in the
study of fertility and its transition. With these distinctions, demographers would be able
to explain whether variations in overall fertility were due to changes in marriage
behaviour, to what extent the observed fertility reduction was the result of falling marital
fertility, and how far the recorded fertility departed from the uncontrolled or natural
fertility. In order to measure changes in fertility, Henry also, in parallel with Norman
Ryder, developed the concept of Parity Progression Ratio, an important fertility indicator
in demography, and the method of computing it (Henry 1953).
Like the efforts made by other demographers at the time, Henry’s initial investigation
was constrained considerably by the lack of data. As pointed out in the last section,
fertility had been falling for several decades if not more than a century in some developed
countries. Their recent demographic data simply did not allow demographers to answer
questions about uncontrolled fertility (if it had existed) and its early reduction. To place
his theory of natural fertility on solid empirical evidence, and to provide detailed
description and explanation of fertility decline, Henry turned to historical population data.
He first examined genealogical records made of Geneva’s ruling class families from the
mid-sixteenth century. The analysis of these records provided considerable insight into
the demographic behaviour of this urban elite and showed that their mortality and fertility
already started declining in the late seventeenth and early eighteenth century (Henry
1956). This population belonged to a special social group, however, and the demographic
patterns recorded among them were expected to be different from those observed in the
general population.
5
To overcome this problem, Henry and his colleagues turned to the surviving parish
records of baptism, burial and marriage of the village of Crulai, in Normandy, France.
These parish records run in an unbroken series from the mid-seventeenth century to the
French Revolution, and provided detailed demographic information. These details
ensured that most of the records could be correctly linked to one another, making them an
invaluable data source for the study of demographic patterns in the past and their
historical changes. In spite of their potential value for demographic research, the parish
records were not originally created for demographic investigation, and they could not be
analysed easily using conventional demographic methods. This provided Henry with a
major methodological challenge. His response was to develop a method that had
similarities to, but was demographically more rigorous than, those previously used by
Hyrenius. This method is now known as family reconstitution and will be further
discussed later in this chapter. With the method, Henry and his colleagues were able to
reconstruct the demographic history for a large proportion of the individuals whose
baptism, marriage and burial records were kept in the parish, to establish the kinship
relation between these people, and to reconstitute their families. The results gave Henry
and his group a rare opportunity to examine the demographic history of Crulai. Their
work led to numerous interesting discoveries about demographic behaviour, and changes
in fertility, mortality, and marriage patterns in Crulai over the period from the midseventeenth century to the French Revolution (Gautier and Henry 1958).
Following this success, large scale family reconstitution studies, overseen by Henry, were
carried out in INED. These studies showed that there were great variations in fertility,
mortality and marriage patterns in France in the last few hundred years, and the variations
were often related to differences or changes in socio-economic and environmental
conditions. These results were subsequently found to be broadly similar to those observed
in other parts of Europe. What distinguished France from its European counterparts was
its early reduction in marital fertility. ‘A demographic revolution’ was witnessed in many
parts of the nation at the time of the French Revolution, long before such changes
occurred in the rest of Europe. These discoveries and the new knowledge gained from
such historical demographic investigations led to a major reinterpretation of early modern
French history (Goubert 1970).
Henry’s pioneering work exerted a profound impact on the advancement of demography
and the investigation of population history. It offered an important conceptual framework
directly linking historical demographic investigations to important contemporary
population issues and applied a powerful method of family reconstitution to parish
registers that were widely available in western countries. Under this influence, historical
demography soon entered an era of repaid development.
2.2. The Cambridge Group and the Advancement of Historical Demography in
England
Another milestone in the development of historical demography was the founding of
Cambridge Group for the History of Population and Social Structure in 1964. As its name
suggests, research activities at the Cambridge Group concentrated, particularly in the
6
early years, largely on the following two areas: (a) population trends in historical England
and their inter-relationship with socio-economic changes; and (b) micro-social structure,
especially household formation and composition, and its impact on the society.
Work on population history at the Cambridge Group also started with family
reconstitution. E. A. Wrigley published his family reconstitution results for Colyton, an
English parish in East Devon, in 1966 (Wrigley 1966a). The paper immediately attracted
the attention of demographers and historians and greatly promoted the development of
historical demography. Wrigley and his colleagues were aware that findings derived from
the family reconstitution for a small area were likely to be affected by random variations
that limited the broader relevance of the results. They therefore launched a much larger
investigation.
Over the next three decades, researchers at the Cambridge Group coordinated family
reconstitution of Anglican registers of many English parishes, which were the most
important data source for the investigation of demographic changes in England before the
modern census started. The work of the Cambridge Group was particularly concentrated
on 26 parishes where better registers were available, and this led to the reconstruction of
their population history between 1580 and 1837. The results of this reconstruction, as
Wrigley and his colleagues evidently show, ‘are representative not only of the
demographic situation of the parishes from which the data were drawn, but also of the
country as a whole’. Their analysis of past demographic behaviours and their outcomes
has been conducted in such detail that now much more has been ‘known about many
aspects of English demography in the parish register period than about the post-1837
period when the Registrar-General collected and published information’ (Wrigley et al.
1997: cover page). Today, English Population History from Family Reconstitution 15801837 is widely seen as one of the most significant and influential books ever published in
historical demography.
Because of the vast amount of work involved in family reconstitution, it is very difficult
to apply the method to a national or sub-national population with a large size. Although
the family reconstitution undertaken in both INED and the Cambridge Group was
conducted by many researchers and took a long time to complete, the total number of
parishes for which the population history was reconstructed consisted of only one per
cent or less of the total number of parishes in historical England and France. Moreover,
while family reconstitution can produce data on population flows such as number of
births, deaths and marriages in a given period, it alone cannot provide information about
population stocks in a particular area which are also subject to the influence of migration.
Without information about total population, aggregate measures such as birth rates, death
rates and natural increase rates cannot be computed. To overcome this limitation and to
make as full use as possible of parish registration data, researchers at the Cambridge
Group undertook, mainly in the 1970s, another investigation into English population
history. This study, using aggregated demographic data collected from 404 parishes and
the method of ‘back projection’ that will be discussed later, produced detailed
demographic estimations for English population for the period between 1541 and 1871.
Based on the reconstructed demographic statistics, E. A. Wrigley and R. S. Schofield
7
thoroughly examined the applicability of the population theory put forward by Malthus
and the relationship between changes in economic conditions especially real wages and
changes in people’s demographic behaviours. Their findings were reported in another
significant publication in historical demography, The Population History of England
1541-1871 (Wrigley and Schofield 1981).
Another major research area vigorously pursued by the Cambridge Group, especially in
the early years since its establishment, was the study of family and household in past
times. Before the 1960s, it was widely believed that large complex households had
predominated in the past and they were only replaced by nuclear households during the
process of industrialization or modernization. Similar views were held concerning the
existence of very early female marriage ages in pre-transition Europe. Peter Laslett
(1915-2001) analyzed surviving population registers collected from two English villages,
Clayworth and Cogenhoe, and showed that the majority of households in the two
populations were small in size and simple in structure even before the Industrial
Revolution (Laslett 1965 and 1966). At about the same time J. Hajnal, one of Laslett’s
close collaborators, identified, using early censuses and listings of inhabitants, the
existence from at least 1500 of a European marriage pattern. He showed that women in
Europe, except for the eastern and southeastern portion, married in their mid-twenties and
up to 20 per cent never married at all, and newly married couples generally set up their
independent households (Hajnal 1965). These results surprised many researchers,
especially family historians.
Under Laslett’s leadership and influence, a large scale international comparative study
was started in Britain and several other countries. The study found that household
formation and composition in historic North and West Europe had the following
characteristics. Large number of children left home in their early or mid-teens and
worked as apprentices or servants in households that were not related to them. Males and
females generally married late, most forming their own households at marriage.
Households were relatively small in size and consisted in most cases of a single nuclear
family. They rarely had more distant kin although the presence of non-relatives was not
uncommon (Laslett and Wall 1972). These characteristics and practices were later
summarized by Hajnal as the nuclear household formation system in contrast to the joint
family system (Hajnal 1983). The research findings provided great insights into microsocial structure in the past, and were essential to our understanding of the relationship
between demographic patterns and changes in economic conditions observed in historical
Europe.
While these discoveries began to shatter widespread beliefs about the pre-modern society
of Western and Northern Europe, England in particular, researchers were aware that the
findings were drawn from a limited number of case studies and might not represent the
general pattern in the national population. There was also the question of whether the
predominance of simple family households observed was the product of demographic
constraints such as low fertility, high mortality, late marriage, and low marriage rates
rather than the outcome of people’s residential preferences or social norms. To examine
these possibilities and other concerns, K. Wachter, E. Hammel, and P. Laslett applied
8
computer micro-simulation and sophisticated statistical analysis to the investigation of
household formation and composition. Their studies helped to confirm Laslett’s early
findings about the pre-modern English household formation system, and brought
computer micro-simulation into the domain of historical research (Wachter et al. 1978).
2.3. The Historical Investigation of Fertility Transition in Europe
At about the same time as the Cambridge Group began its investigations into English
population and social history, another major effort made in historical demography by
scholars in Europe and North America was also launched under the title, the European
Fertility Project. This project, organized by the Office of Population Research at
Princeton University, had two principal objectives: to provide detailed quantitative
information about the fertility experience of over six hundred provinces of Europe during
the period of their demographic transition; and to identify the social and economic
conditions that prevailed at the time when the modern reduction in fertility started (Coale
and Treadway 1986).
Researchers involved in this project collected large amounts of fertility data for more
than six hundred European provinces, recorded over a period of more than one hundred
years (data collected for European aristocracies covered a much longer period). A set of
fertility indices (If, Ig, Ih and Im), which will be discussed later, was developed and
calculated at ten-year intervals for each of the provinces included in the study. Analysis
of these data showed that, while noticeable fertility fluctuations (including reductions)
were observed in pre-transition societies such as England in the mid-seventeenth century,
sustained fertility decline in most European countries other than France only took place
in the late nineteenth century. This decline was far more complicated than that described
by classical demographic transition theory. It was first observed in Northwest Europe,
followed by peripheral areas in Southern and Eastern Europe. If France was excluded,
more than half of the six hundred European provinces began their long-term fertility
decline between 1890 and 1920. While there were provincial leaders and laggards in this
transition, the differences between the onsets of their fertility decline were not very large.
By 1930, most provinces had already witnessed a more than 50 per cent fertility
reduction from their pre-transition level (Watkins 1986).
The European Fertility Project found that in pre-transition societies fertility fluctuations
were often related to changes in marriage patterns, whilst changes in fertility behaviour
within marriage were a major factor explaining the secular fertility decline during the
demographic transition. The project also showed that in most pre-transition populations,
fertility levels of married, or of all, women were considerably lower than among the
Hutterites, a religious group who lived in the United States and Canada and was widely
credited with the highest recorded fertility. Differing from the stylised description offered
by classical demographic transition theory, fertility levels and patterns varied greatly
across regions in pre-transition Europe. Fertility decline tended to start earlier in
populations who lived in urban areas, had better education or experienced a lower infant
mortality than in populations living in rural areas, with less education or experiencing a
relatively high infant mortality; but the relationship between fertility decline and
9
industrialization (as measured by proportion of people engaged in agriculture), levels of
literacy and infant mortality was not strong. The socio-economic conditions under which
fertility began to decline in these European provinces were also remarkably different.
Interestingly, while it is difficult to, on the basis of economic conditions, determine the
threshold of sustained fertility decline, similar fertility changes were often recorded in
populations sharing common cultural tradition, language or religion. Although the
evidence uncovered by the European Fertility Project did not offer a strong support for
the classical demographic transition theory, it significantly enriched our knowledge about
the demographic transition in Europe by providing great insights about pre-transition
fertility regimes, and their profound changes during the late nineteenth century and first
half of the twentieth century.
2.4. Historical Demography in East Asia
Historical demography has also made remarkable progress in East Asia in recent decades.
In Japan, A. Hayami, also strongly influenced by Henry’s family reconstitution work,
started his research in historical demography in the late 1960s. Since then, an increasing
number of studies has been carried out by Japanese scholars, shedding new light on
Japanese population history. According to available evidence, population registration had
already existed in Japan in the eighth century. Records surviving from this period are
often very fragmented, however, and do not provide enough information on which to
base systematic demographic analysis. Most published studies are conducted using
demographic data recorded since the seventeenth century. The primary data sources for
Japanese historical demography are population registers (Ninbetsu Aratame Cho) and
religious faith investigation registers (Shumon Aratame Cho), although other data sources
such as death registers compiled by Buddhist temples, are also used.
On the basis of their examination of these historical data, Japanese scholars considerably
revised previous population estimates for the early Tokugawa period. They have shown
that, although the national population growth stagnated in the late Tokugawa period,
there were marked regional variations in population growth. These variations were
closely related to major disasters taking please during this time, migration to the cities,
and the relatively high mortality recorded in urban areas. Their analysis of surviving
population registers has uncovered much detail about marriage, fertility, mortality,
migration, and residential patterns in pre-modern Japan (Hayami 2001; Saito 1990; Tsuya
and Kurosu 2004). Hayami’s studies, for example, have shown that there were large age
differences between husbands and wives in some historical Japanese populations. Marital
fertility among women born after 1700, those between 1751 and 1800 in particular, was
moderate or low in comparison with that observed in many historical European
populations. The age structure of deaths differed considerably between urban and rural
areas. The studies have also revealed that work-related migration was common in some
regions, where many people worked away from home (dekasegi). These population
movements exerted a notable impact on women’s age at marriage, levels of fertility, and
age patterns of death in urban and rural areas (Hayami 2001).
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China has had a sophisticated population registration system since ancient times and still
possesses a large collection of officially produced demographic statistics. These records,
along with those made privately (for example family genealogies), provide valuable data
sources for historical demography. Although studies of population history have been
confined almost entirely to the examination of summary population figures calculated at
national or provincial levels in Mainland China, great progress has been made in the
analysis of demographic data recorded at the level of individuals in recent decades by
scholars working in Taiwan and western countries.
T. Liu (1992) systematically analysed 50 lineage or family genealogies collected from 12
provinces in China. These genealogies record nearly 300,000 people belonging to more
than 20 generations who lived mostly between the fifteenth and nineteenth centuries. Liu
and her research team examined marriage, fertility, and mortality patterns in the lineages,
their population growth, demographic constraints on household formation, social status of
lineage members, and major socio-economic functions of lineages and families. The
study offers a good example of using genealogical materials for demographic
investigations, and provides remarkably detailed information on population changes
among these lineage populations during China’s Ming-Qing periods (1368-1911).
Another major effort in pursuing Chinese historical demography is the work of J. Lee and
his collaborators. Their studies are based primarily on two types of historical records. The
first is the Qing imperial lineage genealogies, which are of high quality, especially in the
early period. These data provide unique opportunities for the investigation of
demographic behaviour in the population and for the study of fertility and infant
mortality in the past. The second is the population registers of people living in various
parts in China during the eighteenth and nineteenth centuries, which are census-type
records updated (or collected) every three years. Lee and his collaborators have examined
the demographic history of these populations. On the basis of their findings and those
reported by other scholars, they have challenged the Malthusian view that historical
China was ‘the prime example of a society dominated by the positive check and virtually
devoid of any preventive check’. According to Lee and his collaborators, ‘Chinese
demographic behiviour not only provides an alternative demographic model’ to the one
proposed by Malthus; ‘it also reveals that many differences in population behaviour
between East and West are a product of regional and historical differences in social
organization rather than of different population checks’ (Lee and Wang 1999: 5 and 7;
Lee and Campbell 1997).
Studies conducted by T. Telford, S. Harrell and Z. Zhao have also made contributions to
the development of Chinese historical demography. Aside from using genealogical data
and computer micro-simulation to study marriage, fertility, mortality, and potential
residential patterns in the past, these researchers have systematically examined major
under-registration problems found in genealogical records and the potential biases of
using such data in the study of demographic changes (Harrell 1987 and 1995; Telford
1986 and 1990; Zhao 1994 and 2001). Their studies provided useful references for those
who use genealogical records in their research.
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One of the major research findings in Chinese historical demography is that marital
fertility was, as in Japan, relatively low in Chinese history compared with that in many
historical European populations. Chinese women married at relatively young ages, but
their birth intervals (both between marriage and first birth and between successive births)
were relatively long. They also stopped having children at relatively young ages. Some
scholars have suggested that the relatively low marital fertility was an indication of
deliberate control of fertility or family size (Lee and Wang 1999; Zhao 1997). These
findings have important theoretical implications, and have stimulated considerable debate
and much further research into these issues in recent years.
2.5. Historical Demography in Other Areas and Its Recent Development
In addition to the development discussed above, a large number of historical
demographic investigations have been undertaken in Canada, Germany, Italy, Spain,
Sweden, the Netherlands, Austria, the United States of America and many other countries
in the last few decades. Similar studies have also been conducted in Latin America, South
and Southeast Asia, although they tend to be relatively small in scale and carried out by
fewer researchers in comparison with those in other areas. These studies are not detailed
here because they are, in many respects such as methods, data sources, and questions
being examined, similar to those discussed in previous sections. Nonetheless, two recent
developments are worth further commenting.
The first development is observed in some European, especially north European,
countries. Many of these countries possess historical data covering a long period, with
good quality and much detailed information. For example, Sweden began compulsory
parish registration in the second half of the seventeenth century, and since the mideighteenth century, records of causes of death and continuous instrument-based
measurements of surface temperature have also been collected in some areas. Detailed
demographic and non-demographic data of this kind provide researchers with a unique
opportunity to examine many questions that have never been examined before. For
example, historical demographers have, using such data, examined the effects of
childhood experiences such as stress in early life on old age mortality (Bengtsson and
Lindstrom 2000). The richness of these historical data also generates great interest in
inter-disciplinary research among scholars with different academic backgrounds such
demography, epidemiology, history, genetic and environmental sciences. One such
example is a recent investigation of the impact of ambient temperature on the sex ratio at
birth and male longevity, which has been conducted using historical demographic and
meteorologic data collected from Demark, Finland, Norway, and Sweden (Catalano,
Bruckner and Smith 2008).
Another important development in historical demography is the increase in international
research collaboration, as demonstrated by the Eurasia Population and Family History
Project, which was initialized by A. Hayami in 1993. Researchers involved in this project
assembled rich historical data from five countries: Belgium, China, Italy, Japan and
Sweden, which provided detailed social and demographic information for recorded
individuals and their households and communities. Through their examination of these
12
materials, the researchers compared population dynamics in the five countries during the
Eighteenth and Nineteenth centuries. Their research findings have been reported in a
large number of articles and several books and conference proceedings (Bengtsson,
Campbell and Lee 2004). This project has a number of features that distinguish it from
others. First, historical demographic data gathered from these populations have been
analysed using similar and sophisticated statistical methods, which has gone beyond
many previous studies. Second, demographic behaviour of individuals have been
analysed in the context of their household structure, socio-economic profiles of their
community and their social status and positions within the family, which has brought
about considerable insights on how people’s demographic behaviour and its variations
were influenced by cultural values and micro social structure. The research project
provides a good example of international collaboration in advancing historical
demography.
3. Major Data Sources for Historical Demography
Many countries possess rich historical demographic data, and they have become
increasingly accessible in recent years thanks to the progress made in historical
demography and the advancement in computer technologies. This section briefly
describes some of the most important data sources used in the investigation of population
history.
3.1. Parish Registers
Parish registers are records of baptisms, marriages, and burials made by ecclesiastical
authorities. They have been the most widely used and the most rewarding historical data
source in the study of European population history.
Keeping parish records already existed in certain Italian city states in the late medieval
period. The practice spread first to western France and England, then to most of western
and central Europe. By the eighteenth century, registering baptisms, marriages and
burials was widely observed in many European countries and their overseas colonies
(Willigan and Lynch 1982). In England, for example, parish registration was established
in 1538 by Thomas Cromwell (1485-1540) who ordered the clergy to record all baptisms,
marriages, and burials performed in the Christian church. During the next three centuries
continuous efforts were made to maintain and improve such registration. This resulted in
a huge collection of parish registers, many of which are still available today. The
importance of parish registers as major records of vital events and the primary data
source for historical demography was only replaced by the civil registration and modern
censuses during the nineteenth century.
The level of detail of parish records varies considerably across region and over time.
Some entries are very simple and include only the name of the person who was baptised,
buried, or married, and the date of the event. Others give a more elaborate description of
the individuals and families affected by these events. Thus, a baptism record may also
contain the date and the place of birth, the names of the parents, and the occupation or the
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rank of the father. A marriage record may provide information on the ages of the bride
and groom, their past marriage history, their parents’ names, occupation or rank, and the
occupation of the groom. A burial entry may include the age, occupation or rank, normal
place of residence of the deceased, and even the cause of death. In general, the
extensiveness of information contained in parish registers tends to increase over time, and
many detailed records were found in the eighteenth and early nineteenth centuries
(Willigan and Lynch 1982).
While these records may at first glance not seem to be very useful for demographic
analysis, the technique of family reconstitution can transform them into a comprehensive
data set consisting of detailed information on all, or most, of the demographic events
experienced by the recorded individuals. This gives parish registers a privileged position
as the key data source for understanding the demographic history of many European
countries and their overseas colonies from the sixteenth to the early nineteenth centuries.
The parish registers as a major data source for demographic studies have some limitations,
however. As a type of religious records compiled by the Christian church, parish registers
might cover only part of the whole population living in an area. People with other
religious faiths were usually excluded from such registration. Because baptism, marriage,
and burial registration recorded only people involved in such events and did not have
information on migration (except data about those married into the parish), they cannot
provide accurate information on the total population in a parish at any particular point in
time. Moreover, these records do not provide information on residential patterns or coresiding family members, although the relationship between family members may, in
many cases, be determined on the basis of these data.
While parish registers do not exist in non-Christian populations, records sharing a similar
nature were also found in some countries. In historical Japan, for example Kakocho or
Books of the Past, were compiled by many Buddhist Temples. Kakocho also listed people
who had died sometimes including their age at death, causes of death, and the date of
death, providing an important data source that has been used for the study of
demographic change in the past (Hayami 2001; Jannetta and Preston 1991).
3.2. Population Registers and Census-type Materials
While often differing from modern censuses, census-like operations have long existed in
many parts of the world. Governments have collected population data in order to obtain
reliable information for military drafts, corvees, and taxation purpose. Governments or
religious authorities have also gathered the required demographic data through
maintaining and updating various population registers. Thanks to these efforts, a
formidable amount of historical population data has been accumulated in many countries.
In China, for example, aggregated population statistics computed at national, provincial
and prefectural levels for the year 2 AD are still available. Population registers made
during the Tang Dynasty (618-907 AD) have been discovered in Dunhuang. Surviving
records of this kind, especially those made in the last few centuries, have increasingly
14
been found and used in historical demography in recent years (Lee and Campbell 1997;
Liao 2001).
Population registers and census-type materials are particularly abundant in East Asia.
Hukou Ce made in the Qing Dynasty (1616-1911) and used by J. Lee and his
collaborators (Lee and Campbell 1997), Ninbetsu Aratame Cho produced in Japan during
the Tokugawa era (1603-1868) and used by many Japanese scholars (Hayami 2001), and
Hojǒk compiled in Korea over the seventeenth and eighteenth centuries and used by K.
Kim (2005) all belong to this type of records. Historical data of similar nature also exist
in other parts of the world. For example, population registers made in the nineteenth
century have been found in some parts Italy, Belgium and Sweden, and used in recent
investigations of population changes in the past (Campbell 2004; Bengtsson, Campbell
and Lee 2004).
These population registers and census-type materials were generally maintained for
governmental administrative purposes such as tax collection, but they might also have
religious purposes. Shumon Aratami Cho, for example, literally meaning ‘religious faith
investigation registers’. These registers were widely used during Japan’s Tokugawa
period to control the spread of Christianity. They recorded religious beliefs and detailed
demographic information on household members. Similarly, catechetical examination
registers, which are essentially a kind of population register, were produced and used by
clergymen in Sweden to identify eligible parishioners whose knowledge of the Bible was
to be examined (Campbell 2004). Listings of inhabitants were also compiled by
clergymen in some parts of England (Laslett 1966).
Population registers and census-type materials generally record the population living in a
particular area with a clearly defined boundary. Residents are normally listed by
households and the relationship between household members and household heads is
usually indicated. Some registers also include the age, sex, marital status, and occupation
of household members, as well as other useful information such as land holding of the
household. All these properties make the population registers and census-type materials
particularly useful for historical study of micro-social structures. However, records of this
type do not usually include information on number of births, deaths, and marriages, and
therefore do not allow computing birth, death, and marriage rates; although these rates
may be estimated if successive population registers or census data are available.
3.3. Family or Lineage Genealogies
Genealogy is the written record of family or lineage members, which recounts one’s
descent from an ancestor or ancestors by enumeration of the intermediate persons.
Constructing genealogies has a long history, and the practice is found in many societies,
especially those in a new frontier where a large number of migrants settled and those
where lineage organizations formed an important social institution and the worship of
ancestors was widely encouraged. Genealogies vary greatly in their format and levels of
detail. In their simplest form genealogies list lineage or family members and the
relationship between them, but they can also record detailed social demographic
15
information such as dates of birth, death, and marriage, and academic and political
achievements of their members. These records provide a rich mine of information for
historical research.
Genealogies distinguish themselves from other population records in a number of ways.
People recorded in genealogies normally have common ancestry. The generation to
which a recorded member belongs, and the relationship between recorded lineage
members, are all clear. This makes genealogical records very useful in the study of social
mobility of the family, population genetics, and heterogeneity. Differing from most other
population records, which are usually obtained from clearly defined territories, or
particular social or religious groups in certain areas, people recorded in genealogies are
less, if at all, restricted by their place of residence. Because of that genealogies cannot
provide information on the total population of a given region, but they can be very useful
for the study of geographic movements of lineage or family members and migration
patterns if such information is available. Another notable feature of genealogies is that
some extend over many generations and contain much information, which provide rare
opportunities for the study of early population history.
The way in which genealogies are compiled also makes them differ from other historical
population data. Genealogies are often constructed by people of several generations,
usually under different circumstances, and over a long period. The rules of compiling
genealogies, or the implementation of such rules, may change from time to time. The
interval between the time when a certain social demographic event took place and when
the event was recorded in the genealogy could be very long. While genealogical records
have many desirable qualities, in comparison with other historical population data they
are more likely to have suffered from selective biases, which arise mainly from the
following influences.
First, because genealogies were usually constructed for the purpose of recording and
glorifying the history of the family or lineage other than demographic research, certain
family members, for example, children who died young, female descendants who are
often regarded as less important to the family in a patrilineal society, and persons who
have brought disgrace to the family, are frequently excluded from genealogies.
Genealogies also tend to be compiled by families or lineages with relatively high socioeconomic status (Harrell 1987; Telford 1990; Zhao 1994).
Second, genealogies can be constructed in different ways. The compilation of a
genealogy may be started from and by people who lived hundreds or even thousands
years ago, their descendants being later added into the genealogy generation by
generation. This results in a descendant genealogy. Alternatively, a genealogy can be
compiled by a person or a group of people of later generations who trace their ancestors
generation by generation back through time and add them into the genealogy. This
produces an ascendant genealogy. Genealogies compiled in this backward fashion are
most likely to obtain the records of ancestors from church books, vital registrations, or
other data sources. The genealogies, therefore, can be viewed as secondary data sources.
Since ascendant genealogies require that each generation to have at least one member
16
surviving into adulthood and to produce at least one child, they tend to exhibit lower
mortality and higher fertility than the general population.
Third, many available genealogies are records of lineages that survived to the time when
the genealogies were updated last time or collected, which could be hundreds of years
since the start of their compilation. One reason, among many, that these lineages could
avoid extinction is that they have experienced favourable demographic conditions such as
higher fertility, lower mortality, young ages of marriage, and higher proportion marrying,
which all promote population growth. Among survival patrilineages that extend through
the male line, sex ratios may also be higher than the population as a whole. Biases of this
kind tend to be found in the first few generations recorded in a genealogy, and their
impact becomes less observable thereafter (Zhao 2001).
3.4. Other Data Sources
While parish registers, population registers, census-type materials, family and lineage
genealogies are the most widely used data in historical demography, other data sources
are available and can be used in the study of population history as well. In one of the
earliest books devoted to historical demography, T. H. Hollingsworth listed nineteen data
sources that, in addition to those already discussed above, include Bills of Mortality, vital
registration data, fiscal documents, military records, inventories of property, wills,
marriage settlements, eye-witness estimates, long-term price records, the number and
extent of towns, archaeological remains, methods of agricultural economy, ecclesiastical
and administrative geography, new buildings, colonization of new land, cemetery data
from both skeletons and tombstone inscriptions (Hollingsworth 1969). The list can be
extended further. For example, detailed land registers made in Chinese history,
biographical information on ‘virtuous women’ and ‘faithful widows’ kept in historical
Chinese county record books, convict indents which detailed the convicts sent to
Australia, and other migration records such as ship lists could all provide useful
demographic information and have been used in the study of past population changes. In
comparison with the data sources discussed in the previous three sub-sections, these data
tend to be less common, more selective and more difficult to handle. They are, therefore,
less frequently used in demographic research.
Aside from historical data recorded at the level of individuals or households, many
countries also accumulated considerable amounts of aggregated population statistics (for
example population totals by regions) throughout their history. These data also shed light
on population changes in the past and can be used in historical demography. Fluctuations
in recorded population totals often reflect both actual demographic changes and the
strength and influence of the government or the size of the area under its jurisdiction.
Statistics of this kind can also be influenced by the purposes of, and procedures used in,
collecting these data, and suffer from various types of under or over registrations.
A further data source that is of great importance for the international comparative study
of population history consists of various demographic databases recently constructed
around the world. One such example is IPUMS-International (Integrated Public Use
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Microdata Series – International). The project began in 1999 and is managed by the
Population Centre at the University of Minnesota. Its objective is to inventory, preserve,
harmonize, and disseminate census microdata collected around world. By the year 2002,
a preliminary database comprising 48 million people in six countries was already released.
Since then much larger amounts of census data obtained from many more countries have
been added into the database and subsequently released worldwide. Although most of
these census records were collected in the twentieth century, they will increasingly
become an important data source for the study of recent population history. Another
example is the HMD (Human Mortality Database) created by the Department of
Demography at University of California, Berkeley and the Max Planck Institute for
Demographic Research. This database, which contains detailed mortality data collected
from more than 30 countries over the last three centuries, has already been used in more
than 200 studies.
4. Methodological Development
Because historical demographers are often required to work with surviving population
data that were not collected for the purpose of demographic research and thus difficult to
use, they have frequently turned to non-conventional and sometimes sophisticated
methods to accomplish their analysis. Partly for this reason, historical demography has
made several major contributions to the advancement of demographic techniques over the
past half century. Some of these developments are summarized in the following subsections.
4.1. Family Reconstitution
Family reconstitution is a technique of record linkage. It brings together scattered
demographic information from baptism, marriage and burial records, and reconstructs the
demographic history of individuals and their families. The technique is widely used by
historical demographers in Europe and North America where large numbers of parish
registers are available (Levine 2003).
High quality parish records are the foundation for family reconstitution. Detailed baptism,
marriage and burial records give information about a person’s birth and childbearing
(date of birth or baptism, the name of the new-born, the names of the parents and maybe
the occupation of the father), marriage (date of marriage, the names and ages of the bride
and groom and sometimes their marriage history) and death (date of death or burial, the
name, sex and age of the deceased). When linked together, these records could provide a
detailed account of the demographic history for an individual and important information
for his or her immediate family members.
Family reconstitution can be carried out either manually or by computers. To assemble
available demographic and sometimes non-demographic information relating to a
marriage, Henry developed the Family Reconstitution Form (FRF). The FRF or similar
forms were used widely by historical demographers involved in family reconstitution
studies before computer software was developed to complete the task. Although not
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exactly the same, these forms are generally used to record the date of the marriage, dates
of birth (or baptism) and death (or burial) of the husband and wife, and dates of birth (or
baptism) and death (or burial) of their children. Occasionally, related socio-economic
information is also recorded on these forms. The linked data are then analysed using
conventional demographic methods to generate required population statistics (Fleury and
Henry 1956; Wrigley 1966b). When performed manually, family reconstitution is very
time consuming. Partly for this reason, many early studies involved only a small number
of parishes. Rapid advances in computer technology have prompted the development of
computer-based and more efficient methods of record linkage. Thanks to this
improvement, large scale family reconstitution studies have been conducted successfully
in several countries in the world.
Family reconstitution is a very effective way of deriving useful demographic information
from baptism, marriage, and burial records. Demographic history reconstructed using this
method sometimes provides more detailed and reliable information than that obtained
from retrospective surveys, which may be biased by respondent’s recall errors. Moreover,
because parish registration was maintained for hundreds of years in many countries,
demographic records generated through linking these registers have become one of the
most significant data sources for the study of long-term population changes.
Because of the constraint imposed by parish registers that allow only births, marriages,
and deaths to be inferred from recorded religious activities such as baptism, marriage
ceremonies, and burials, family reconstitution alone can generate data about population
flows (such as total number of births, deaths and marriages in a specified period), but not
population stocks. Furthermore, information about migration such as moves into (except
through marriage) and out of the parish cannot be obtained from parish registers or family
reconstitution. Demographic results revealed by family reconstitution could, therefore, be
affected by selection biases if people who moved away from the parish behaved
differently from those who did not. This possibility should be examined whenever such
inquiries could be conducted.
4.2. Inverse Projection, Back Projection, and Generalised Inverse Projection
In addition to providing opportunities for reconstructing demographic history for millions
of recorded individuals through family reconstitution, parish registers generate large
amounts of aggregated demographic data such as total numbers of recorded births (or
baptisms) and deaths (or burials) in a population or an area. How these summary data
might be used in the study of population history of a region or country was another major
challenge that faced researchers in the early years of the development of historical
demography.
A breakthrough was achieved when R. Lee developed the method of inverse projection in
the early 1970s and used it to estimate detailed fertility and mortality rates for historical
English populations. Lee’s method is based on assumptions about age-specific mortality
and fertility schedules and migration, and requires information about population size and
age distribution at a given time in the study period. It can then use a sequence of births
19
and deaths recorded over time to derive sequences of vital rates and age distributions of
the population at any time or time interval over this period. The method uses a technique
that is similar to population projection but in an inverse form. Here, the inversion is not
temporal but logical, in the sense that the method differs from the conventional
population projection where sequences of births, deaths and age distributions are derived
from a given sequence of vital rates and a starting population. Theoretically, the method
of inverse projection ‘can be used either forward or backward in time’ (Lee 1974: 495).
On the basis of the inverse projection, J. Oeppen developed the method of back
projection. This method uses totals of births and deaths recorded in a period and
information about population size and age composition at the point in time as its input
parameters. On the basis of ‘assumptions (or direct information) about certain other
characteristics of the population, such as the age patterns of mortality and net migration’,
it projects the population backward in time. The method of back projection can provide
detailed demographic estimates such as population size and age distribution, crude birth
and death rates, gross and net reproduction rates, expectation of life at birth, and other
useful information at any time interval considered appropriate, or specified, by the
researcher (Wrigley et al. 1997: 7). The method was used by Wrigley and Schofield in
their study, The Population History of England 1541-1871, to produce detailed
demographic data for historical English population over a period of more than three
centuries.
While back projection was regarded as an important technical breakthrough in historical
demography, it was open to a number of criticisms, however (Lee 1985 and 2004). Partly
as a response to these criticisms, J. Oeppen improved his early method and developed it
to a wider class of models that he termed ‘Generalized Inverse Projection’ (GIP), within
which both back projection and inverse projection can be defined. According to Oeppen,
General Inverse Projection ‘provides a flexible framework for the consistent integration
of data and a priori information to produce constrained demographic projections. The
basic structure can be applied to problems in population reconstruction, interpolation, and
data correction’. Oeppen’s refined method allows researchers to estimate a series of
mortality and migration parameters ‘that correspond to the period for which totals of
births and deaths are available, and, simultaneously, a series of population age structures
that are consistent with the data and the parameters’ (Oeppen 1993: 245-246). In addition
to Generalized Inverse Projection, other related techniques such as Differentiated Inverse
Projection and Stochastic Inverse Projection have also been developed on the basis of the
Inverse Projection pioneered by Lee. These methods have been used to study long-term
demographic patterns, their changes over time, and the relationship between those
changes and economic development. Detailed information about these developments can
be found in D. Reher and R. S. Schofield (1993) and E. Barbi, S. Bertino and E. Sonnino
(2004).
4.3. Computer Simulation
Computer simulation is a technique in which researchers use computers to mimic ‘reality’,
conduct ‘experiments’, and examine the impact of given events in which they are
20
interested. The technique is increasingly used to study questions that are too difficult, or
not possible, for conventional methods to handle. Computer simulation is neither new nor
does it belong to population studies alone, but it has played an important part in
advancing historical demography, as evident in the development and use of two computer
micro-simulation systems: SOCSIM and CAMSIM.
As mentioned earlier, when, in the early 1960s, P. Laslett made his important discoveries
about household composition in historical England, it became necessary to test the
validity of these research findings and to establish that the high proportion of simple
family households recorded in English history was indeed a result of people’s residential
propensity. To do this, K. Wachter, E. Hammel, P. Laslett and other researchers
developed a sophisticated computer simulation system SOCSIM. Their simulation
investigations of household formation in past times led to the publication of a landmark
work, Statistical Studies of Historical Social Structure (Wachter, Hammel and Laslett
1978). Following this initial success, J. Smith and J. Oeppen developed another computer
simulation system CAMSIM (Smith 1987; Smith and Oeppen 1993).
SOCSIM and CAMSIM share a number of similarities. Both of them are computer
micro-simulation systems in which all demographic events are simulated at the level of
individuals rather than at the level of population or sub-population groups as in a macrosimulation. The two systems are capable of addressing both the central tendency in
people’s demographic behavior and outcomes, and their intra-population variability. Both
SOCSIM and CAMSIM are ‘stochastic’ and execute all demographic events randomly
according to the probabilities that govern the occurrence of those events. This allows
researchers to examine not only the deterministic aspect of the demographic process, but
also the impact of chance. Both simulation systems were initially designed for the
historical investigation of kinship structure and household composition, and have been
used widely in historical demography, studies of changing kinship structure in
contemporary and future populations, and investigations of other theoretical and
methodological issues. In spite of their similarities, however, SOCSIM and CAMSIM
differ notably in their system designs, major assumptions and simulated outcomes. These
technical details, which are crucial for using the systems and interpreting their results, are
discussed in a number of publications (Hammel, Mason and Wachter 1990; Smith 1987;
Smith and Oeppen 1993).
Computer demographic simulation differs from empirical research by nature. In
simulation studies, a model population is generated by the computer. Changes in the
population and their implications are simulated under the demographic conditions
determined by input demographic parameters. These conditions can be manipulated
according to the research design. Computer simulation can handle complicated
demographic processes, and the simulation can be conducted repeatedly under the same
or different conditions. This is very useful in measuring the impact of chance and in
identifying the influence of major factors being studied. Because of these characteristics
and its effectiveness in examining complex issues, computer simulation has become an
important aid for historical demographers. The two systems mentioned above have been
used in a large number of studies (Zhao 2006). In addition to SOCSIM and CAMSIM,
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other demographic simulation systems (for example MOMSIM) have also been
developed and applied in historical demography (Ruggles 1987). Their use has made
important contributions to our understanding of population and social history in recent
decades. It is important, however, to note that in the real world observed population
changes or other social phenomena are affected by many interrelated factors. In contrast,
computer demographic simulation takes into account only the factors that have been
specified in the simulation system. Accordingly, simulation results tell us about the
implications of the theory and assumptions that are embedded, both explicitly and
implicitly, in the process of simulation, not about what has actually happened in a real
world. Simulation results differ from, and should not be mistaken for, reality.
4.4. Coale’s Fertility Indices and Other Methodological Developments
The European Fertility Project discussed in section two also made considerable
methodological contributions to the development of historical demography and
population studies. This project was designed to exploit the wealth of information
contained in summary demographic data gathered from some six hundred European
provinces in the nineteenth and twentieth centuries and to compare fertility patterns
across regions and over time. To achieve this, Ansley Coale (1917-2002) developed a set
of fertility indices (If, Ig, Ih, and Im). If, Ig and Ih indicate relative levels of general fertility,
marital fertility and non-marital fertility; Im indicates the proportion of married. Using
these indices, researchers involved in the project successfully showed how observed
general, marital and non-marital fertility levels differed from ‘a clearly defined maximum
fertility’ as indicated by fertility rates among the Hutterites, and the extent to which the
general fertility was affected by the levels of marital and non-marital fertility, and by
patterns of marriage in all European populations included in the study (Coale 1986: 162).
Methodological developments have also been made in other research areas such as record
linkage, the analysis of household composition, the evaluation and correction of historical
data, and the use of genealogical records and other less common historical materials.
Some of these techniques and methods are relatively easy to understand and have been
widely used (for example, methods used in studying household composition), while
others are still in the early stages of development, or tend to be data source specific and
have only limited use. Therefore, discussion about the development of these techniques
and methods is not presented here.
5. Concluding Remarks: Historical Demography at the Beginning of the Twentyfirst Century
This chapter provides an introduction to the history of historical demography, its
principal data sources, and major methodological developments made in recent decades.
The discussion has concentrated on conventionally defined historical demography – the
application of demographic techniques to historical data. Some topics have not been
discussed though they are also related to population history. One such topic is
paleodemography, the study of demographic characters of ancient populations. The other
is qualitative historical demography promoted by D. Kertzer and others (Kertzer 1997).
22
While these research areas are important for our understanding of people’s demographic
behaviours in past times, their underlying causes, and implications, they have not been
discussed in this chapter because the methods, evidence and information used in
paleodemography and qualitative historical demography differ considerably from those
used in conventional historical demography.
Historical demography has made impressive progress since it was established as a
research discipline half a century ago. Scholars have assembled a vast quantity of
surviving population records, from which they have derived valuable demographic
information through the use of family reconstitution or other ingeniously developed
methods. These efforts have generated considerable insights into demographic behaviour,
population changes, and their interaction with socio-economic development in the last
few centuries, which have provided crucial empirical evidence for major demographic
theories. Methodological developments made in historical demography have also greatly
advanced population studies. Whilst remarkable achievements have been made in
historical demography in Europe, North America and East Asia, much remains to be done
in other parts of the world.
In the light of these achievements, it is clear that more effort should be made to promote
historical demography as a means of advancing understanding of modern demographic
problems, especially in the areas where such studies are still rare. One of the most
important findings of historical demography is the great diversity in demographic
behaviours and in demographic responses to emerging changes in social, economic or
environmental conditions. Although detailed historical demographic investigations have
been conducted in limited numbers of populations, they reveal significant variations in
patterns of marriage, levels of fertility, and ways of controlling family size. Knowledge
of pre-transition societies has had significant implications on the development and
interpretation of population theory. Many current demographic theories, models and
methods have been developed based on demographic experiences of limited countries,
especially developed countries. While these theories play an important role in guiding
demographic research and these models and methods proved to be useful in population
studies undertaken in other areas, there is a risk that some of these theories, models or
methods may not be applicable to demographic reality of these populations. This is a
problem that has to be addressed if we want to gain a better understanding of world
population issues. If for no other reason, this concern alone justifies the importance of
further promoting historical demography in the world.
Further effort should be made to improve the use of historical data and to promote
research collaboration. More attention should be given to the linkage and use of records
from different sources, for example, linking parish registers and vital registration data to
census records, jointly using household registers and genealogical data, and jointly using
demographic and non-demographic data. Operations of this kind provide opportunities
for researchers to identify registration problems in different data sets, to overcome the
limitations of the data of a particular type, and to examine the questions that could not be
studied using records from a single source. Another important step in advancing
historical demography is to further promote research collaboration between historical
23
demographers from different countries and collaboration among scholars from disciplines.
This is particularly helpful in countries where historical demography is in the early stages
of development and major investigations into population history often call for multidisciplinary effort.
Conditions for advancing historical demography have been greatly improved over the last
few decades. We have gained much experience in using historical data for demographic
research. Increasing amounts of surviving historical data have been collected, catalogued
and made in computer readable forms. Researchers no longer need to spend extensive
resources on gathering and inputting records. Many studies can now be conducted on a
scale that could hardly be imagined a couple of decades ago. Increasing computing power
and the development of many techniques and analytical tools make historical
demography a less challenging task than ever before. In this favourable environment, the
early twenty-first century is expected to see a further boom in historical demography in
the world.
24
Glossary
Historical demography – the application of demographic techniques to historical
population data.
Demographic transition – the historical shift of fertility and mortality from both high to
both low. The term also refers to the model describing this change.
Natural fertility – the level of fertility that would prevail if couples do not alter their
reproductive behaviour according to the number of children already born.
Parity progression ratio – the progression of women who already have n children go on
to have at least another child.
Parish registers – registers of baptisms, marriages and burials made by Christian
churches in many European countries.
Genealogies – records recounting one’s descent from an ancestor or ancestors by
enumeration of the intermediate persons.
Family reconstitution – a method linking together separately-recorded vital events in
order to reconstitute the demographic history of individuals and their families.
Computer demographic simulation – the technique of using a computer program to
model and study demographic processes and their outcomes.
Acknowledgement
The author would like to thank Richard Smith, Tommy Bengtsson, and Mac Boot for
their comments on earlier versions of this chapter.
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Biographical Sketch
Zhongwei Zhao is Professor at the Australian Demographic and Social Research Institute,
College of Arts and Social Sciences, Australian National University. He studied at Peking
University, University of Exeter, and obtained a Ph.D. from the University of Cambridge.
Prior to taking up the present appointment, he was a senior research associate at the
Cambridge Group for the History of Population and Social Structure and a Bye-Fellow at
Pembroke College, University of Cambridge, a research fellow, fellow, and senior fellow
at the Demography Program, Research School of Social Sciences, Australian National
University. Zhongwei Zhao has been doing research in the following areas: simulating
changes in kinship structure and household composition, fertility behaviour in historical
and contemporary China, using genealogies for demographic research, changes in kinship
networks in Victorian England, and examining the Far Eastern mortality model and the
United Nations 1982 model life tables. At present, his major research activities
concentrate on investigating health transition and mortality changes in East Asia. He has
published many articles in world leading demography and social history journals.
31