Geographical Inequalities and Population

Change in Britain, 1971-2011

Chris Lloyd, Nick Bearman, Gemma Catney Centre for Spatial Demographics Research, University of Liverpool, UK

Email: c.d.lloyd@liverpool.ac.uk

Twitter: @lloydcd

BSPS 2015, University of Leeds, 7-9 September

Outline

1. Population Change and Geographic

Inequalities in the UK, 1971-2011: ESRC project

outline

2. Creating population surfaces

3. Population change 1971-2011: some

provisional analyses

Project outline

• Identification of comparable variables from the UK Censuses

of 1971, 1981, 1991, 2001 and 2011

• Creation of population surfaces for Britain for all comparable

variables (1km cells nationally and 100m cells for urban areas;

in Northern Ireland grid square counts for 1971-2011 are

already available)

• Provision of population surfaces, code in R programming

language to manipulate data and an online atlas of

population change

Project due to complete July 2016

Creating population surfaces

• Selected comparable variables for 1971, 1981, 1991, 2001

and 2011

• Overlay enumeration districts or output areas with landuse data (or using postcodes, etc)

• Use areal weighting to estimate populations of each

populated area (e.g., landuse not water)

• Overlay output with1km grid • Use areal weighting to estimate populations of each

populated segment

• Aggregate counts within grid cells

• Smooth grid cells to make neighbouring cells similar

In the provisional analysis which follows, simple overlay of

EDs/OAs and a 1 km grid is conducted with no smoothing

Population change 1971-2011

• Population surfaces generated for 1971 and 2001 for

- Total persons

- Unemployed persons (% of employed and unemployed)

- Non owner occupied households (%)

- Households without access to a car or van (%)

- Households with more than one person per room (%)

• From the latter four, z scores were derived (percentage-

mean / standard deviation) and these were summed to

derive a deprivation score (following Townsend)

• Gridded counts and difference maps (2011-1971)

- Total persons, Unemployed persons (%), Townsend score

• Analysis of population spatial distribution using index of

dissimilarity and Moran’s I autocorrelation coefficient

• Correlations between counts/percentages/scores for 1971 and 2011

Total persons in 2011 Total persons 2011-1971

Unemployed persons (%) in 2011 Unemployed persons 2011-1971

Townsend score in 2011 Townsend score 2011-1971

Unevenness and clustering: 1971 and 2011

Index of dissimilarity, D

Unemployed Non Own Occ HH No Car HH > 1 PPR Townsend

1971 0.793 0.767 0.809 0.852 0.789

2011 0.724 0.726 0.759 0.726 0.719

Moran’s I (queen contiguity) for percentages and Townsend

deprivation score

Unemployed Non Own Occ HH No Car HH > 1 PPR

1971 0.224 0.423 0.298 0.328

2011 0.226 0.348 0.327 0.406

Unevenness and clustering

• Decrease in clustering by unemployment, housing tenure,

car and van access and overcrowding (and thus deprivation

as a whole)

• Decrease in unevenness of the population by housing

tenure (impact of right to buy?), • Increase in unevenness by car and van access and

overcrowding

These findings appear to reflect an increased urban-rural contrast (clustering – the tendency for neighbouring areas to

be alike – will decrease if urban areas become more distinct

from suburban areas while unevenness will increase)

Characterising spatial structure

z(xi) is a percentage, or

score at location xi

p(h) is the number of data

pairs separated by the lag

(distance and direction) h

Variogram: spatial dependence at different spatial scales

2)(

1

)}()({)(2

1)(ˆ hxx

hh

h

ii

p

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zzp

1. Take each data value in turn and compute its squared

difference from each of the other values in the data set and store

the distances between them

2. Group these differences into distance bins – e.g., all squared

differences for pairs separated by 1 to 2 km and compute half of

the average of these differences

3. Plot these (half) average differences against distances

4. The plot shows how difference between values changes as a

function of distance

Bounded variogram model: nugget and effect and spherical component.

Provides a composite measure of clustering and polarisation: small nugget

indicates localised clustering – with a large sill this indicates polarisation

Variogram model

Simulated surfaces: spherical model with a = 2 and 40.

Variograms

Variograms for Townsend scores: 1971 and 2011

Increased variation in 2011 but also greater spatial continuity in

scores over regional scales (larger ranges)

Relationships between 1971 and 2011 counts, percentages and deprivation scores

Correlation coefficient for percentages (all significant at

the 0.01 level)

Tota

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Un

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plo

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No

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Occ

HH

No

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HH

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1p

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2011 2011 2011 2011 2011 2011 Total persons 1971 0.934 Unemployed 1971 0.176 Non Own Occ 1971 0.516 HH No Car 1971 0.569 HH gt 1ppr 1971 0.113 Townsend 1971 0.406

Relationships between 1971 and 2011 counts, percentages and deprivation scores

Correlation coefficient for percentages (all significant at

the 0.01 level)

Tota

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rso

ns

Un

em

plo

yed

No

n O

wn

Occ

HH

No

Car

HH

gt

1p

pr

Tow

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2011 2011 2011 2011 2011 2011 Total persons 1971 0.929 Unemployed 1971 0.252 Non Own Occ 1971 0.515 HH No Car 1971 0.698 HH gt 1ppr 1971 0.248 Townsend 1971 0.583

For cells >= 25 people in 1971 and 2011

Summary • The provisional analyses indicate the value of being able to explore population change over small areas

• Large decreases in total population (2011-1971) highlighted

in some urban areas, with increases in parts of London and

other areas away from the larger cities and towns

• Suggestion that unemployment and deprivation (Townsend

score) increased in urban areas

• Decrease in unevenness of the population by housing

tenure, increase in unevenness by car and van access and

overcrowding

• The resource will enable geographically- and attribute-rich

analyses of population change in the UK and, specifically, the

ways in which the population has become more or less

geographically unequal

Acknowledgements

Support from the ESRC is acknowledged gratefully

(Grant Ref No ES/L014769/1). Team members also

include Alex Singleton and Paul Williamson and

Richard Prothero at the ONS.

The Office for National Statistics are thanked for

provision of the data.

Office for National Statistics, 2011 Census: Digitised

Boundary Data (England and Wales) [computer file].

ESRC/JISC Census Programme, Census Geography

Data Unit (UKBORDERS), EDINA (University of

Edinburgh)/Census Dissemination Unit. Census output is

Crown copyright and is reproduced with the

permission of the Controller of HMSO and the Queen's

Printer for Scotland.