Developments in Output Geography for 2011 Census ESRC 2011 Census conference, 7-8 July 2011 Andy Tait ONS Geography
Overview Changing UK geography Stabilising our geography –Statistical building bricks –Geography policy for National Statistics Plans for 2011 Census geography
UK Geography – why its 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
Denmark10 Estonia10 Greece10 Latvia10 Hungary10 Sweden10 Belgium5 Cyprus5 Lux5 Malta5 Austria5 Portugal5 Ireland0 Bulgaria50 Poland40 Slovakia30 Finland30 Czech Republic20 Spain20 France20 Italy20 Lithuania20 Netherlands20 Slovenia20 Amount of admin boundary change in Europe each year
1995 Counties and UAs
1998 Counties and UAs By date of introduction
Avon – Pre LGR; counties (and districts)
1996 – Post LGR: UAs
Boundary change LGR in Cornwall 2009
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 ndependent.gov.uk/ ndependent.gov.uk/ Parliamentary Constituencies 5 year Reviews Reduce constituencies by 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
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 1998 Index of Deprivation 2007
Lower 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
Population of blue higher geography = 138
2. Use of stable small area building blocks 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 Population of blue higher geography Exact = 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 1 st January Maintenance Process Boundary Products Jan DecJanDecJanDec Changes to wards in 2010Changes 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 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 geography Postcodes Census address register Ward/parish changes since 2003 Administrative re-organisation Positional accuracy of boundaries
Changes since 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 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 they have been split by local authority boundary change since 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 not align to real-world features 2.3 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 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
Thank you. Questions? tel: +44 (0)