This appendix explains the indirect estimation of infant and child mortality using a worked example to illustrate the basic principles of the techniques and to identify some of the important concepts and assumptions involved. The example uses the numbers of children ever born and children who have died by marital duration for the whole of England and Wales given in the published volumes of the 1911 census.

Indirect techniques involve the use of fertility and mortality schedules. Fertility schedules are a series of fertility rates calculated for different age groups or marital duration groups of women, which describe a childbearing pattern among a cross-section of women at a particular time (a period schedule) or among women born in a particular period (a cohort schedule). Similarly, a mortality schedule is a series of mortality rates, or probabilities of dying for different ages, which describe a mortality regime among a cross-section or a cohort. Life tables are the most common form of mortality schedule, providing the probability of surviving from birth to any exact age.

Calculation of the probability of dying

Brass noticed that of the children born to women in a particular fiveyear marital duration group the proportion who have died corresponds roughly to the probability of dying before a certain exact age.

From census enumerators' books to data files

Once the enumeration district clusters or sectors chosen to represent each of the 13 locales in each census year had been identified, the information recorded in the relevant enumerators' returns had to be converted into computerised data files.

The transcription of the returns to magnetic tape was carried out by OPCS to maintain the confidentiality of the original material. Names and addresses were not transcribed so that anonymity was provided, but otherwise the files were as far as practically possible a faithful transcription of the original returns.

The files brought with them two sets of problems which had to be addressed before analysis could proceed. The first set of difficulties were those created by the census-taking process itself, while the second set were encountered when transforming the transcribed records into an analysable dataset. The present section deals with the latter set first, outlining the pitfalls faced and the remedies adopted. Sections 3.2 and 3.3 then address the issues arising from the changing nature of the census-taking process and procedures, before sections 3.4 and 3.5 lay out the analytical concepts and expediencies utilised within the research framework in order to overcome the constraints of the data.

On receipt of the data tapes a series of checks verifying the accuracy of the source material and of the transcription was carried out, and amendments were made to the files where necessary. Then, in order to facilitate subsequent analyses, most of the fields of information within the data files were systematically coded.

Environment and demographic change

In chapter 1 it was argued that understanding of fertility and nuptiality change in England and Wales, particularly during the critical half-century before the 1911 Fertility Census, has been strongly constrained by the preoccupations of those compiling the original report from that census. Interpretation of the changes in the survival chances of young children also continues to be much influenced by the agenda set by late Victorian and Edwardian investigators. Chapter 1 concluded by holding out the prospect that the small but significant amount of individual-level ‘raw data’ from the 1911 census inquiry available to the present study would result in a range of new, relatively independent empirical findings. Has this volume succeeded in getting behind and going beyond the Edwardians' agenda? What have been the principal findings, and what directions for future research are indicated?

This concluding chapter will not attempt to recapitulate or summarise all the detailed points to emerge from the analyses reported in chapters 4 to 6. Rather it will try to draw out the principal findings of general significance – those which revise or challenge previous views of the ways in which fertility, nuptiality and mortality changed in England and Wales.

This book would not have been written had it not been for a meeting, in the mid-1980s, between Peter Laslett and Roger Thatcher, the then Registrar-General. Neither fertility nor the survival chances of young children was the original focus of their discussions, but their vision of comparative historical research across space and time made the present study possible.

The four authors came together from a diversity of academic disciplines; history, geography and demography, and this has encouraged us to take an interdisciplinary approach to our subject. Realisation that we were not always ‘talking the same language’ led us, within the constraints of the space available, to lay out the methods, techniques and assumptions used in an effort to make our work more transparent for readers drawn from across a spectrum of disciplines. Our book has been laid out in the expectation that readers may wish to go straight to chapters which interest them, but with the hope that they might feel drawn to follow cross-references to investigate more fully the interconnections between fertility and mortality, geography and history, sources and methods.

Our work, we gratefully acknowledge, has been supported throughout by funding from the Economic and Social Research Council (ESRC), and has formed part of the research programme of the Cambridge Group for the History of Population and Social Structure.

The ordinary least squares (OLS) method of multiple regression modelling is used here, although for the statistically minded it is worth noting that the mortality index that we are using as the dependent variable can never be negative, and this may render simple OLS regression unsuitable as dependent variables are assumed to vary between negative and positive infinity. In practice, there may also be a large grouping of values of the mortality index on zero, as a considerable proportion of women will not have experienced any child deaths. This may make a tobit regression more suitable. Trussell and Preston, however, present a thorough comparison of the use of OLS and tobit regressions with reference to infant mortality, using the mortality index as the dependent variable. They conclude that OLS regression produces almost identical results to tobit.

Although tobit regression is probably more statistically valid, it has the crucial disadvantage of being much less straightforward to interpret than OLS. In a comparison using our data, the overall pattern of the magnitudes and signs of the coefficients was the same with both regression procedures, but while the OLS average is constrained to be that of the sample of the whole, this is not true for tobit. It is therefore not possible to interpret the tobit coefficients as having a particular multiplicative effect on mortality.

The fast-changing demography of England and Wales, c. 1880–1920

Profound social and demographic changes were underway within British society as the nineteenth century waned. The four decades straddling Queen Victoria's epoch-closing demise in 1901 were witness to the dawning of a new era in the nation's family life. Marriage patterns, birth rates, infant and child mortality, family sizes, sexual behaviour and sexual attitudes, the position of the elderly, and the typical compositions of households in terms of children, servants and boarders, were all changing relatively rapidly between the late-1870s and the 1920s, when compared with the preceding and succeeding half-centuries.

This is reflected in strong movements of the basic demographic indices. Whereas the crude death rate of England and Wales had remained fairly constant, somewhat above 20 deaths per thousand persons, since civil vital registration began in 1837, from 1881 it fell continually to a figure of 14 per thousand by 1910–12 and 12 per thousand by 1920–2, after which the rate of decline slowed markedly. Similarly, the crude birth rate, having fluctuated quite substantially, between rates of 32 and 37 per thousand persons since 1837, fell unambiguously from the late 1870s, to a figure of just under 25 per thousand by 1911, subsequently settling at a level of just over 15 per thousand throughout the 1930s. Figure 1.1.1 shows these general trends within a wider chronological context.

Introduction

As pointed out in the introductory chapter, while considerable progress has been made in charting and understanding the progress and nature of the declines in fertility and infant mortality in the late nineteenth and early twentieth centuries, the lack of data on the family building experiences of individual couples has constrained researchers' ability to understand fully the network of factors encouraging and enabling the population of England and Wales to have fewer, healthier children. With the civil registers of births, marriages and deaths closed to researchers, there has been little opportunity to undertake the detailed analysis of child bearing and rearing patterns possible for earlier centuries through the technique of ‘family reconstitution’.

One source which has been repeatedly plundered for information on the initiation and acceleration of fertility decline and infant survival has been the published reports from the 1911 Fertility Census authored by T. H. C. Stevenson. By using the data on ‘children born alive’ and ‘children dead’ supplied by individual couples, carefully discarding those married women who were not living with their husbands on census night, and standardising his measures of fertility and child survival to remove any distorting effect arising from differences in the average age at marriage or in the average marital duration of mothers, Stevenson was able to demonstrate occupational and spatial variations in both fertility and child survival.