Memorandum by the Office for National
Statistics (ONS) (WB 09)
SUMMARY
1. The Office for National Statistics (ONS)
produces a wide range of statistics which are used by Government
to identify the need for and to monitor the impact of policy.
More specifically the Neighbourhood Statistics function, established
as a result of the Policy Action Team 18 Report—Better Information,
is charged with the production and dissemination of statistics
at the neighbourhood level. The ONS therefore strongly welcomes
this opportunity to comment upon the issue of Electoral Ward Boundaries.
2. The ONS has established a framework of
stable building blocks, (called Output Areas and Super Output
Areas) which are currently being used for the collection and publication
of small area statistics via Neighbourhood Statistics. These building
blocks together with improved geographical referencing will increasingly
form the basis for other National Statistics.
3. The ONS is currently involved in a joint
research project with the Ordnance Survey to assess the work involved
and an appropriate timetable for aligning Output Area and Super
Output Area boundaries with the Ordnance Surveys' MasterMap framework.
Once aligned the resultant set of boundaries
will reflect identifiable areas on the ground using established
features such as roads to mark boundaries. Output Areas and Super
Output Areas would bring a number of advantages if used in building
electoral areas.
4. The ONS strongly recommends that the
Output Area and Super Output Area building blocks should be taken
into account when determining changes to electoral areas. If whole
statistical building blocks are used to construct electoral wards,
a wide range of statistical information would be available to
inform the decisions on where boundaries should be drawn, to better
reflect local conditions and patterns of demography relevant to
the electoral process.
An alignment of future boundaries with this
set of stable building blocks would allow:
— the production of higher quality
statistics for electoral areas and local communities, including
improved information on changes over time and the impact of policies;
— improved ability to integrate data
between central and local government sources; and
— a simpler and more efficient approach
to maintaining boundaries using better information about the underlying
population.
5. The ONS also recommends that joint work
should be initiated between the ONS and the Electoral Commission
to assess the options and timetable for the adoption of the Output
Area and Super Output Area building blocks.
BACKGROUND
6. The degree of boundary change in England,
together with the way in which electoral boundaries are currently
constructed, causes severe problems for the production of reliable
time-series data for small areas. For example in the extreme case
of 2002 no fewer than 1,555 wards (18% of the 8,429 in England
at the end of 2001) were changed.
7. The ONS recognises that electoral boundary
change in order to ensure fair representation is appropriate;
however changes involving small geographical areas present significant
problems for statisticians. Firstly discontinuities in time series
may mask important underlying changes. Secondly, to ensure information
about residents in the area subject to change remains confidential
it may prove necessary to withhold statistics from general release.
THE NEW
BUILDING BLOCK
GEOGRAPHIES
8. The Cabinet Office's `Report of Policy
Action Team 18 : Better Information' (April 2000) highlighted
a critical need for better information about local areas. Specifically
recommendation 2 of PAT 18 states ". . . Government should
ensure (unless there are good reasons to the contrary) that .
. . administrative boundary changes at district level and below
are minimised". The ONS were charged with developing Neighbourhood
Statistics and the new approach to geographic referencing required
to enable the production of better local statistics for England
(and Wales).
9. A key element of the solution is the
establishment of a framework of stable building blocks (Output
Areas and Super Output Areas) which are now being used for the
collection and publication of all small area statistics for Neighbourhood
Statistics and will increasingly be used for other National Statistics.
— The smallest of these building blocks
(and so the lowest layer in the hierarchy) are the Output Areas
(OAs) as created for the publication of the 2001 Census statistics.
— The next three layers in the hierarchy
are the "Super Output Areas" (SOAs). Each layer is formed
automatically by grouping together building blocks from the layer
below it. The result is a nationally consistent set of geographic
building blocks created specifically for the collection and publication
of statistics.
— At the top of the hierarchy are Local
Authority Districts (LA) and Unitary Authorities (UA). Figure
1 indicates how the layers of the hierarchy relate to each other
and to the electoral geography.
Note: The average population of electoral
wards is subject to considerable variation. Whilst the average
population of wards is 6,000 the smallest electoral ward has a
population of 106 and the largest has a population 35,102 (source
2001 Census), this can prevent meaningful comparisons between
electoral wards. Super Output Areas have been developed with the
aim of facilitating cross area comparisons.
10. These building blocks have been designed
to provide better statistics about local communities. They have
been built to include a known resident population, will be maintained
and will increasingly become the basis of all National Statistics
outputs.
The Super Output Areas have already been used
for the publication of the 2004 Indices of Deprivation and are
increasingly being adopted for analysis and publication by Local
Government. These Output Areas and Super Output Areas will also
form the fundamental building blocks for outputs from the next
Census in 2011.
11. The Output Areas and Super Output Areas
will be maintained by the ONS. They will remain frozen wherever
possible but, inevitably, some may be subject to change to take
account of areas of significant population change. It is anticipated
that such changes will be dealt with by splitting or merging the
area affected rather than re-working a large number of areas.
This approach means that Super Output Areas will form excellent
denominators to inform decisions on future boundary changes.
12. In the future it is anticipated that
all National Statistics for administrative and electoral areas
(such as wards) will be built by geographically referenced data
using the Output Area and Super Output Area building blocks. Where
meaningful statistics are required for areas that cannot be created
from the Super Output Area building blocks some degree of estimation
and best fitting will be required. Output Areas and Super Output
Areas were initially aligned with electoral ward boundaries but
any future boundary change which does not take account of these
building blocks will progressively break the relationship. Building
new electoral and administrative boundaries from these blocks
will ensure a richer and higher quality source of data for local
areas.
13. It is understood that the Electoral
Commission will be increasing its utilisation of Geographic Information
Systems (GIS) for a range of applications. A significant GIS application
is the production of electronic digital boundaries. The ONS strongly
recommends that a single set of digital boundaries is produced
for each boundary change which can be used, under controlled conditions,
by each organisation involved in the boundary change process.
This will prevent duplication of effort, reduce risk of boundary
discrepancies and errors, and facilitate the earlier release of
finalised boundaries. The ONS has a key requirement to produce
timely adjusted statistics to reflect areas subject to boundary
change and the early release of quality digital boundaries would
improve its ability to meet this requirement.
14. Within the European Community the need
for comparable regional statistics led to the introduction of
the Nomenclature of Units for Territorial Statistics (NUTS). This
is a hierarchical classification of spatial units that provides
a breakdown of the European Union's territory for the purposes
of producing comparable regional statistics.
15. The Review of Statistics for Economic
Policy Making, undertaken by Christopher Allsopp at the instigation
of the Chancellor, recognises the work that has been carried out
within the ONS on the development of geographic building blocks.
Paragraph 24 of the final report states:
24. The NUTS hierarchy is now widely accepted
across a broad range of statistical and administrative bodies.
It should ideally be the standard, at the very least at the NUTS
1 level and where possible at lower levels, unless there are overriding
operational reasons to do otherwise. We welcome the ONS' proposals
for a more stable small-area geography. Any new classifications
that are introduced should where possible be built up from this
proposed geography.
ALIGNING THE
BUILDING BLOCKS
WITH MASTERMAP
16. The ONS is currently involved in joint
research with Ordnance Survey to enable the alignment of the Output
Area and Super Output Area building block units with Ordnance
Survey's MasterMap framework.
The alignment will result in a set of boundaries
which reflect identifiable areas on the ground. Again these building
blocks would seem to have a number of advantages for building
electoral areas—they will align with MasterMap, be identifiable
on the ground using established features such as roads to mark
boundaries and will form a key part of the Digital National Framework
(DNF) development being led by Ordnance Survey.
RECOMMENDATIONS
17. The ONS would make the following recommendations:
— The ONS strongly recommends that
the Output Area and Super Output Area building blocks are taken
into account in the consideration of future changes to electoral
areas.
— Once the building blocks have been
fully aligned to Ordnance Survey's MasterMap (perhaps by 2007),
they should form the base for all boundary changes (that is—changed
electoral boundaries should be aligned to these building blocks).
— Joint work should be put in place
between ONS and the Boundary Committee to consider how this step
might be best managed with the intention of adopting from 2007
onward.
18. An alignment of future boundary change
with this set of stable building blocks would offer:
— the production of better statistics
for electoral areas and about local communities—including
better information about change over time and the impact of policies;
— improvements in the ability to integrate
data between central and local government sources; and
— a simpler and more efficient approach
to maintaining boundaries based on better information about the
underlying population.
19. Joint work should be put in place between
the ONS and the Electoral Commission to assess the options and
associated timetable. The target for this work should be the adoption
of Output Area and Super Output Area building blocks for the construction
of new electoral boundaries from April 2007 onwards.
20. It is strongly recommended that a single
set of digital boundaries is used by those organisations involved
in the boundary change process.
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