Geographies and populations Where are the boundaries?
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Transcript of Geographies and populations Where are the boundaries?
Geographies and populations
Where are the boundaries?
Paul Norman
School of GeographyUniversity of Leeds
Acknowledgements
• ESRC ONS GROS NISRA OS UKBORDERS CDU ESDS
• ESRC Research Awards RES-165-25-0032, RES-189-25-0162
NHS Information Centre, 21st March 2011
Geographies and populations
• What is a ‘geography’? How are geographies defined?• What is a population? How are they defined?• Health measures by areas and by population subgroups• What else do geographers do with health data?
• Challenges of time-series analysis: changing boundaries and population definitions
• What geography & which population?• Aspects of the DH White Paper
Geographical boundariesTerritoriality
River Tweed
Offa’s Dyke
49th Parallel Some large lakes & a river
Vancouver Island
Natural• Coastline• Rivers
Arbitrary / artificial• Defend• Tradition• Organise• Political• Ownership• Legal
Examples of geographies• Traditional geographies
– Counties, parishes• Electoral geographies
– Constituencies, wards• Administrative geographies
– National / local government, census• Functional geographies
– Postal– Emergency services: police, fire, ambulance– Health; Education– Utilities: gas, electricity, water, sewerage– Sport
• Planning regions– Enterprise zones, regeneration areas– National Parks, nature reserves
What is a population?• Count of people … in a defined geographical area• Differentiated by
– Age & sex; Ethnic group; Social Class (or SEG or NS-SEC)– Educational achievement; Tenure
Area 1 Area 2
Area 3 Area 5Area 4
What do geographers, demographers, social scientists, do?
Self-reported health, 1991
Mortality, 1991
0.0
0.5
1.0
1.5
2.0
2.5
3.0
SC I SC II SC IIIN SC IIIM SC IV SC V
Od
ds
Rat
ioWhat do geographers, etc, do?
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
White Indian Pakistani &other South
Asians
Chinese Blackgroups
Other
Od
ds
Rat
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0.0
1.0
2.0
3.0
4.0
5.0
6.0
Ow ner occupiers Private renters Public renters Institutions
Od
ds
Rat
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Tenure
Social Class Ethnicity
Self-reported health: limiting long-term illness, 2001
Area distribution
Area distributions of health outcome
Model residuals
Area profiles: classification
Deprivation distribution
k-means classification
Poor health cluster
Good health cluster
Student cluster
Point distribution of health outcome?
Analysing point data
Kernel density map
Clusters
What about change over time?
… 1988-1996 1997-2003
2004-2005 …
No ward stays exactly the same during the period(East is almost the same though)
Tricky due to boundary change …
Peterborough: 1988 - 2005
What about change over time?
1991 1999
2004
Soon …All change please!
“The redisorganisation of the NHS”Smith J, Walshe K, Hunter D (2001) BMJ: 323: 1262-3
• Administrative boundary change: due to
– Need for good governance (re-organise subnational structure of
administrative geography) &
– Differential population change by small areas & need for equity in
electoral representation
• Census boundary change: due to
– Many census geographies aligned with administrative geographies
(as above) &
– Need for a local geography which protects confidentiality yet
delivers usable statistics, & thus may be time point specific
• Lead to boundaries being re-drawn
– But this severely hampers comparison of cross-sections
– Census & other applications may need consistent geographical
areas over time for analysis of change
Why do boundaries change?
Time-series: infant mortality rates
1981 1986 1991 1996 2001 2006
0
5
10
15
20
25
1970-72 1980-82 1990-92 2000-02 2004-06
Infa
nt
Mo
rta
lity
Ra
te
Q1: least deprived Q2 Q3 Q4 Q5: most deprived
0.50
0.75
1.00
1.25
1.50
1980 1985 1990 1995 2000 2005
Infa
nt
Mo
rtal
ity
Rat
ios
Cities and Services London Suburbs London Centre
London Cosmopolitan Prospering UK Coastal and Countryside
Mining and Manufacturing
IMR relative to national rate
Deprivation Supergroups
What about change over time?1991 Ethnic groups
2001 Ethnic groups
Social Class to NS-SEC
Why (not) change? Administrative, census & survey data, etc• Historical record versus contemporary relevance?• Continuity versus current applicability? • Reactive versus proactive?
‘Right’ geographies & ‘right’ populations? • Confidentiality: tension between providing …
Detailed demographic data
Coarse geographic scale
Detailed geographic scale
Banded demographic detail
Nation Region District SyntheticWard
Output AreasSuper Output Areas
‘Healthy Lives, Health People: Our Strategy for public health in England’
Geographical & population aspects to be resolved• Life expectancy between the richest and poorest neighbourhoods (p.16)• One ward in Kensington and Chelsea … compared with … one of the capital’s poorer wards (p.15)• Neighbourhood income level (p.16)• Data will be published to make it easier for local communities to compare themselves with others across the country (p.26) • Department for Communities and Local Government will support local areas with streamlined planning policy that aligns social, economic, environmental and health priorities into one place (p.40)• GP consortia will have responsibility for the whole population in their area (p.62)
Community? Neighbourhood?
Indian, Pakistani, Bangladeshi
Students
Community? Neighbourhood?
‘Healthy Lives, Health People: Our Strategy for public health in England’
Community? Neighbourhood?
Anne Milton, Under Secretary of State for Public Health 11/01/2011
“We generally take a lead from the Office for National Statistics and use Super Output areas (lower and/or middle layer) for small area analysis”
“Terms such as, for example, communities or neighbourhoods referred to in publications should be interpreted as plain English terms that in analysis would be represented by an appropriate standard geography”
‘Healthy Lives, Health People: Our Strategy for public health in England’
GP consortia?• p.62 GP consortia will have responsibility for the whole population in their area
Anne Milton Under Secretary of State for Public Health 11/01/2011
“The White Paper makes clear that GP consortia will have to have an area of geographical focus. Work on this is still ongoing but it is likely that this will be based on existing standard geographies”
‘Healthy Lives, Health People: Our Strategy for public health in England’
GP consortia? Likely to be within a local authoritybut #1 … Edge effects & wider catchment
‘Healthy Lives, Health People: Our Strategy for public health in England’
GP consortia? Likely to be within a local authoritybut #2 … People are different & from different areas
Geographies and populationsWhere are the boundaries?
Need consistency over time: geographies & populationsNeed also to have contemporary / ongoing relevanceGood policy decisions & appraisals of success need to be underpinned by good data
“Data will be published to make it easier for local communities to compare themselves with others across the country”“Local areas with streamlined planning policy that aligns social, economic, environmental and health priorities into one place”
Needs• Global shift by data providers: a ‘can do’ attitude• Georeferencing: e.g. postcode > OA > SOA linkages• Back revisions of existing datasets• 2021 Census & / or a real replacement