developments in output geography for 2011 census esrc 2011 census conference, 7-8 july 2011 andy...
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Developments in Output Geography for 2011 Census
ESRC 2011 Census conference, 7-8 July 2011
Andy TaitONS Geography
Overview
• Changing UK geography
• Stabilising our geography – Statistical building bricks– Geography policy for National Statistics
• Plans for 2011 Census geography
UK Geography – why it’s a problem
• There are a lot of them
• They change all the time
• Postcodes/addresses
• Boundary change
• New geographies
• They do not align with each other
• Different codes/names used to describe them
Country
Government Office Regions
Counties
Local Authority Districts
Electoral Wards
Complexity and number
Denmark 10
Estonia 10
Greece 10
Latvia 10
Hungary 10
Sweden 10
Belgium 5
Cyprus 5
Lux 5
Malta 5
Austria 5
Portugal 5
Ireland 0
Bulgaria 50
Poland 40
Slovakia 30
Finland 30
Czech Republic 20
Spain 20
France 20
Italy 20
Lithuania 20
Netherlands 20
Slovenia 20
Amount of admin boundary change in Europe each year
1000
300
120
1995
Counties and UAs
1998
Counties and UAs
By date of introduction
Avon1995
1995 – Pre LGR; counties (and districts)
1996 – Post LGR: UAs
Boundary change LGR in Cornwall2009
Health Geography in England
Health Geography in England
New for 201?
GP Consortia
Boundary change - statutory instruments (SI)
• Local government electoral arrangements
• External LA boundaries - Principal Area Boundary Reviews
• Internal - Ward boundaries and names
• Structural Reviews – one tier/UA proposals
• Was The Boundary Committee for England
• http://boundarycommissionforengland.independent.gov.uk/
• Parliamentary Constituencies• 5 year Reviews • Reduce constituencies by 31 • 533 MPs to 502• Electors - min 72,810, max 80,473
Yorkshire and Humberside
Yorkshire and Humber
Yorkshire and the Humber
Yorkshire and The Humber
2001 Output Areas - why
• Census output geography separated from data collection geography
• a geography created from Census data
• consistent size in population/no of households
• socially homogeneous
• meets confidentiality thresholds
• aligns with 2003 administrative boundaries
• Consistent throughout UK
2001 Output Areas
• 175,434 Output Areas• Mean 297 persons; 123
households• Freely available digital
boundary data • Building blocks for
“neighbourhood” geographies: Super Output Areas (LSOAs, MSOAs)
Image courtesy of David Martin. This work is based on data provided through EDINA UKBORDERS with the support of the ESRC and JISC and uses boundary material which is copyright of the Crown.
2001 Output Areas – achieved size
• hhds
• Pop
0
10000
20000
30000
40000
50000
60000
70000
40 - 49 50 - 59 60 - 69 70 - 79 80 - 89 90 - 99 100 -109
110 -119
120 -129
130 -139
140 -149
150 -159
160 -169
170 –179
180 -189
190 -199
200+
Household range
0
10000
20000
30000
40000
100 -124
125 -149
150 -174
175 -199
200 -224
225 -249
250 -274
275 -299
300 -324
325 -349
350 -374
375 -399
400 -424
425 -449
450 -474
475 -499
500+
Population range
Super Output Areas (SOAs)
• created 2004, for Neighbourhood Statistics
• groupings of Output Areas
• layered hierarchy – lower, middle, upper layers
• each layer with size thresholds and targets offer levels of statistical reporting
• Lower SOAs ≈ approx 35,000 OAs, avge pop ≈ 1,500 - created automatically
• Middle SOAs ≈ approx 7,000 OAs, avge pop ≈ 7,200 - created automatically – modified locally
• Upper SOAs not created
Wards 1998Wards 1998
Index of Deprivation 2007Index of Deprivation 2007
Index of Deprivation 2007Index of Deprivation 2007
Lower Layer SOAs 2004Lower Layer SOAs 2004
Geography Policy for National Statistics
1. Geographic referencing of source data
2. Using stable small area building blocks
3. Standard Area Measurements
4. Minimising impact of boundary change on statistics
5. Creating, Naming and Coding for UK statistical geographies
6. Presentation order for statistical outputs
• Use stable geographies as building blocks for creation of National Statistics
• Exact outputs for small areas should be produced and published for these core geographies
• Output Areas/Super Output Areas as building blocks
2. Use of stable small area building blocks
2. Use of stable small area building blocks
4 2 3 4 6 3 4 6
1 6 2 3 5 2 3 5
6 9 2 5 1 2 5 3
1 8 6 3 4 6 3 4
2 3 5 2 3 5 2 3
4 2 3 4 6 3 4 6
1 6 2 3 5 2 3 5
6 9 2 5 6 2 5 9
1 8 6 3 4 6 3 4
2 3 5 2 3 5 2 3
2. Use of stable small area building blocks
4 2 3 4 6 3 4 6
1 6 2 3 5 2 3 5
6 9 2 5 1 2 5 3
1 8 6 3 4 6 3 4
2 3 5 2 3 5 2 3
4 2 3 4 6 3 4 6
1 6 2 3 5 2 3 5
6 9 2 5 6 2 5 9
1 8 6 3 4 6 3 4
2 3 5 2 3 5 2 3
Population of blue higher geography = 138
2. Use of stable small area building blocks
4 2 3 4 6 3 4 6
1 6 2 3 5 2 3 5
6 9 2 5 1 2 5 3
1 8 6 3 4 6 3 4
2 3 5 2 3 5 2 3
4 2 3 4 6 3 4 6
1 6 2 3 5 2 3 5
6 9 2 5 6 2 5 9
1 8 6 3 4 6 3 4
2 3 5 2 3 5 2 3
Boundary of blue higher geography changes. Cuts through 2 OA building blocks. Are the 2 affected OAs in or out of the new boundary?
2. Use of stable small area building blocks
4 2 3 4 6 3 4 6
1 6 2 3 5 2 3 5
6 9 2 5 1 2 5 3
1 8 6 3 4 6 3 4
2 3 5 2 3 5 2 3
4 2 3 4 6 3 4 6
1 6 2 3 5 2 3 5
6 9 2 5 6 2 5 9
1 8 6 3 4 6 3 4
2 3 5 2 3 5 2 3
Population of blue higher geography
Exact = 133-138
Best-fit = 135
OAs best-fitted to blue boundary on basis of its 2001 Census population
An OA is either “all-in” or “all-out”
4. Minimising impact of boundary change on statistics
• Administrative boundary changes should become effective on 1st January
MaintenanceProcess
Boundary Products
2010 2011 2012
Jan Dec Jan Dec Jan Dec
Changes to wards in 2010 Changes to wards in 2011
Ward boundary 2010 Ward boundary 2011
Changes to wards in 2012
5. Creation, naming and coding of UK statistical geographies
• Standard names and codes should be used for all geographic areas
• Naming and Coding Policy – key features:- Non re-use of codes, will not change if name change- Supported by Register of Codes (central metadata service) - Code History Database
• What does this mean?- OA codes will change- SOA codes already in new structure- lookups between old and new codes
5. Creation, naming and coding of UK statistical geographies
• Inconsistent names and codes used across government
• 9 character code
• Over 41k LSOA and MSOA and over 8K Scottish instances are already in this format
• Went live on 1 January 2011
A NN NNNNNN
Area entity e.g. County Unique instance
Alpha - Country
Changes since 2001 - population
• Population growth, especially migration• More and smaller households • Newly built properties
– Greenfield/new land– Brownfield/in-filling
• Sub-division of existing properties• Changing socio-economic
characteristics of areas
Changes since 2001 - geography
• Postcodes• Census address register • Ward/parish changes since 2003• Administrative re-organisation • “Positional accuracy” of boundaries
Changes since 2001 - geography
What do users want? - Consultation 2007
Strong support for:• Stability with 2001 (but reflect change!)• Easy/free licensing of boundaries• Mean high water boundary set• England/Scotland alignment
Some support for: • Aligning boundaries to real world features• Separating communal establishments• Retaining postcode blocks v street blocks• Building a separate set of zones based on workplace• Building separate OAs with no population• Building an Upper layer of SOAs
OA/SOAs – “not fit for purpose” ?
• Address outstanding areas of policy not resolved by the 2007 consultation.- Geography for workplace statistics
- Yes please
- Upper Layer SOAs- Not really
- ‘Badly Performing’ OA/SOAs- 120 OAs and 61 LSOAs accepted for
redesign
- 2011 Census Output Geography Policy- Support
2010 Output Geography consultation
2011 Census Output Geography Policy
• ONS will maintain the stability of the OA/SOA hierarchy between 2001 and 2011
OAs/SOAs will be redesigned only where:
1.1 they have undergone significant population change since 2001
1.2 they have been split by local authority boundary change since 2003
1.3 they have been independently assessed as lacking social homogeneity.
2011 Census Output Geography Policy
2. Redesign of OAs/SOAs limited to maximum 5% of total OA/SOA hierarchy.
Redesigned through splits and mergers of current hierarchy, to support comparability between 2001 and 2011, and other national statistics
Where OAs/SOAs are redesigned they will:
2.1 not align to ward and parish boundaries that have changed since 2003
2.2 not align to real-world features2.3 not contain only a single large communal establishment 2.4 not contain less than 100 persons and 40 households
3. OAs/SOAs split by local authority boundary change since 2003 will be aligned to the changed LA boundary
4.OAs/SOAs will be aligned at the Scotland/England border
5.ONS will provide boundaries for Clipped to the Coastline, as well as to Extent of the Realm
2011 Census Output Geography Policy
6. OAs/SOAs will be recoded to bring them in line with the coding and naming policy that forms part of the Geography Policy for National Statistics
9 character codes• A new geography specifically for the publication of
workplace statistics will be developed as part of the 2011 Census.
Workplace Zones
8. An Upper Super Output Area (USOA) layer will not be created as part of the 2011 Census Geography Outputs
2011 Census Output Geography Policy
9. Boundaries for OAs/SOAs and Workplace Zones will be freely available, subject to agreement with third parties
10. 2011 Census statistical outputs will be produced in line with the Geography Policy for National Statistics 2011 geographies, best-fit
11. ONS will continue to provide lookup products between postcodes and the Output Area hierarchy despite the degradation of the relationship between postcodes and Output Areas, established for 2001 Census
2011 Census Output Geography Policy
• Boundaries • Lookups
- from 2011 postcodes to 2011 higher geographies
- from 2011 OA/LSOA/MSOA to 2011 higher geographies
- from 2001 OA/LSOA/MSOA to 2011 OA/SOA/MSOAs
• Postcode population counts
2011 Census Output Geography Outputs
