Geographies and populations

Where are the boundaries?

Paul Norman

School of GeographyUniversity of Leeds

p.d.norman@leeds.ac.uk

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

io

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

io

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