Geographical Inequalities and Population Change in Britain,

Transcription

1 Geographical Inequalities and Population Change in Britain, Chris Lloyd, Nick Bearman, Gemma Catney Centre for Spatial Demographics Research, University of Liverpool, UK BSPS 2015, University of Leeds, 7-9 September

2 Outline 1. Population Change and Geographic Inequalities in the UK, : ESRC project outline 2. Creating population surfaces 3. Population change : some provisional analyses

3 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 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

4 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

5 Population change 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 (percentagemean / standard deviation) and these were summed to derive a deprivation score (following Townsend) Gridded counts and difference maps ( ) - 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

6 Total persons in 2011 Total persons

7 Unemployed persons (%) in 2011 Unemployed persons

8 Townsend score in 2011 Townsend score

9 Unevenness and clustering: 1971 and 2011 Unemployed Non Own Occ HH No Car HH > 1 PPR Index of dissimilarity, D Unemployed Non Own Occ HH No Car HH > 1 PPR Townsend Moran s I (queen contiguity) for percentages and Townsend deprivation score

10 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)

11 Characterising spatial structure Variogram: spatial dependence at different spatial scales ˆ ( h) 1 2 p( h) p( h) i 1 { z( x i ) z( x i h)} 2 z(x i ) is a percentage, or score at location x i p(h) is the number of data pairs separated by the lag (distance and direction) h 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

12 Variogram model 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

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

14 Variograms for Townsend scores: 1971 and 2011 Increased variation in 2011 but also greater spatial continuity in scores over regional scales (larger ranges)

15 Total persons Unemployed Non Own Occ HH No Car HH gt 1ppr Townsend Relationships between 1971 and 2011 counts, percentages and deprivation scores Total persons Unemployed Non Own Occ HH No Car HH gt 1ppr Townsend Correlation coefficient for percentages (all significant at the 0.01 level)

16 Total persons Unemployed Non Own Occ HH No Car HH gt 1ppr Townsend Relationships between 1971 and 2011 counts, percentages and deprivation scores Total persons Unemployed Non Own Occ HH No Car HH gt 1ppr Townsend Correlation coefficient for percentages (all significant at the 0.01 level) For cells >= 25 people in 1971 and 2011

17 Summary The provisional analyses indicate the value of being able to explore population change over small areas Large decreases in total population ( ) 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

18 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.