Estimating Parish Populations from the Bills of Mortality

Creating a historical GIS environment has been the primary goal of this project, but without detailed information about parish population figures it is impossible to make best use of the mapping environment.  Population density, crimes or deaths or wealth per 1000 individuals, is impossible to map without consistent data about the numbers of people living in each parish.  For the period before the 1801 census, there are only a few ways of generating these figures.  For this project we have chosen to use the Bills of Mortality – the contemporary published accounts of how many people were born and died in the capital, year by year.  This is not a perfect or unproblematic  source. The Bills record burials, rather than local deaths, and suffer from an inconsistent relationship between the two.

A sample page from the Bills of Mortality for 1743

In some parish, such as St Ann Soho, more people were buried than died; while in others, the opposite was true.  The Bills also omit parishes that by the 1740s contained significant areas of urban development.  In other words, the Bills provide only an indication of parochial populations, and then, only when aggregated over several years.  We have attempted to minimise these problems by first, aggregating deaths across whole decades (the 1690s and 1740s) and applying a ‘Correction Factor’ to address issues of under-registration, drawn from John Landers’ Death and the Metropolis (p.166).  The decades chosen correspond with those for which we have large scale datasets that benefit from comparison to population figures.  John Landers’ ‘Correction Factors’ incorporate the impact of both under-recording of local deaths resulting from infant mortality prior to baptism, and the burial of non-conformists.  The relevant multipliers are  1.0128 for the 1690s, and 1.0164 for the 1740s; and are based on retrospective ‘parish register’ data contained in the nineteenth century censuses.

To arrive at a population figure for each parish, the average annual corrected death rate as calculated by Landers needed to be turned in to a population figure.  In the 1740s, Landers estimates the crude death rate for London as a whole as 46.0 deaths per 1000 of the population.  By dividing 1000 by 46.0, a multiplier is generated (21.74), that can be applied to the burial statistics from the Bills to generate a population figure.(Landers, p. 175).  There is no equivalent estimate of the crude death rate available for the 1690s, and the earliest date for which a figure can be identified is the 1730s.  This figure (48.6 deaths per 1000 of the population) has been used to generate a multiplier of 20.58 to arrive at the parish figures for the 1690s. (Landers, p.175).

An additional population figure for 1800 for each parish, has been taken from the 1801 census returns.

In the nature of this process these figures – based as they are on both uncertain data, and a range of difficult assumptions – are approximations, and are probably better used to compare the geographical distribution of London’s population, rather than as a basis for estimates of the population as a whole.  We are also hoping to verify and adjust these figures by comparing them to population estimates developed by E.A. Wrigley for each hundred in England for the period from 1761 onwards, and also by working forward from figures based on the Hearth Tax Returns from the 1670s.

A spreadsheet of the figures being used in this exercise can be found here:  Population from the Bills of Mortality

Bibliography.

John Landers, Death and the Metropolis: Studies in the Demographic History of London, 1670-1830 (Cambridge, CUP, 1993).

Jeremy Boulton and Leonard Schwarz, ‘Yet another inquiry into the trustworthiness of eighteenth-century London’s Bills of Mortality’, Local Population Studies, no.85, Autumn 2010, pp.28-45.

Peter Razzell and Christine Spence, ‘The history of infant, child and adult mortality in London, 1550-1850’, The London Journal,  vol.32, no.3, Nov. 2007, pp. 271-292.

L. D. Schwarz, London in the Age of Industrialisation (Cambridge, CUP, 1992), ch.5.

T. Birch, A Collection of the Yearly Bills of Mortality from 1657 to 1758 inclusive… (London, 1759).

1801 Census, Abstract of the Answers and Returns under the Act for taking Account of the Population of Britain (BPP, 1802, VI).

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