Geography use in Neighbourhood Statistics...
Main Content
Geography Policies
Data within Neighbourhood Statistics according to the Geography Policy for National Statistics (Pdf 56Kb) and the Neighbourhood Statistics Geography Policy (Pdf 600Kb).
The Policies set out the principles for using geographic information to produce and disseminate statistics, particularly at small area level.
The policies also address issues associated with dealing with areas which are subject to boundary changes which can make accurate dissemination of data, and change over time comparisons, very difficult.
This approach outlined, which aims to improve the availability and usefulness of small area statistics, comprises three separate elements:
- The use of a new set of stable building blocks - the Output Areas and Super Output Areas
- Adding grid references to records and referencing as much data as possible at the address level
- Minimising the impact of boundary change standardising the date on which administrative area boundary changes become effective for statistics.
The policies describes these elements and provide guidance for those supplying data to Neighbourhood Statistics and also for those using Neighbourhood Statistics.
Frequently Asked Questions about Neighbourhood Statistics Geography
How can I find data for my Parish? Guidance for Parishes, Communities and other small areas can be found here.
When I type in my postcode, the boundary on the Neighbourhood Statistics map doesn't look right - Using postcodes to link to geographic areas is useful, but has its limitations, the main purpose of a postcode is to enable Royal Mail to deliver letters. Postcode boundaries are subject to continuous change due to new addresses, single addresses acquiring large user postcodes as mail volume increases, and the need to restrict the number of addresses per unit to less than 100. Areas can also be recoded and codes can be re-used in a different place after just two years.
Maps within Neighbourhood Statistics are used to illustrate data and to assist in comparing one area with another, and, while every effort is taken to ensure geographic accuracy, it is not always possible to achieve this.
The default geography within Neighbourhood Statistics is the Super Output Area (SOA), which is designed to be a stable, small area building block, SOAs are intended as a purely statistical geography, and although they allow for detailed small area data, they are not intended to represent communities or large non-statistical structures.
The National Statistics Geography Policy underpins geographic dissemination within NeSS, this policy allows for a 'best fit' option where a larger, geographic entity, such as a ward, does not exactly correspond with the boundaries of the smaller building block units. Please see this article for an example of how this 'best fit' methodology works.
While the maps within Neighbourhood Statistics are reasonably accurate in most instances, they are mainly intended to add context to data or to give an indication of where a small building block unit, such as a SOA lies within a larger area to assist in the visualisation of data. They are not intended to provide pin point accuracy of particular structures, especially when a building block unit could straddle a particular boundary.
Where there is any uncertainty or a discrepancy relating to a boundary or structure within NeSS, information provided by Ordnance Survey should be considered as the definitive source as this will be based on absolute location rather than being assigned as part of the National Statistics 'best fit' methodology.
In any query regarding the location of a boundary or location in a boundary, any map produced by the Ordnance Survey should be acknowledged as being a true representation of a geographic area .
When I produce a Thematic Map map using the 2011 Statistical Hierarchy it looks completely different to one I produced using the 2001 Statistical Hierarchy and there are blanks in the map. Why is this?
Due to changes in population numbers from 2001 and 2011 there has been an increase in the number of Output Areas and Lower Layer Super Output Areas, please see this guidance for more information.
This means that, whereas using 2001 Census data and the 2001 Statistical hierarchy, my map looks like this:
Map produced using 2001 Census data with the 2001 Statistical Hierarchy
Using the same 2001 data with the 2011 Statistical hierarchy produces a map like this:
Map produced using 2001 Census data with the 2011 Statistical Hierarchy
This is because the area has changed between the censuses and you are not comparing identical geographic entities. The first map shows the area as it was at the time of the 2001 Census, the second map shows the same area changed as a result of the 2011 Census.
How do I know if my areas has changed?
ONS Geography have produced a series of reference tables to show those areas which have changed since the 2001 Census and how they compare to the 2011 Census.
Wards by their nature are subject to frequent boundary reviews, this can involve several changes over time which makes providing data to a specific ward boundary difficult. ONS Geography maintain a Ward History Database which tracks changes to ward boundaries over time.
I don't know what the individual postcodes are, how can I get a postcode look up file? ONS Geography now provides National Statistics Postcode Products free of charge as a download. They can also be ordered on CD or DVD, although a charge may apply if ordered in this way.
How does Neighbourhood Statistics apply data to an area - In many instances, the data will be loaded against actual known boundaries and the resulting outputs will reflect these boundaries, there will however be instances were this has not been possible due to a variety of factors, for example the data has not been collected at that particular level, or boundaries have changed over time.
To get around these issues, Neighbourhood Statistics uses three approaches, these are:
-
Aggregation - When the area for which data is required can be built from the area at which data have been provided
-
Best Fitting - When the area for which data are required cannot be exactly built from the areas at which the data has been provided
-
Recasting - the application of a statistical technique to transfer data for all of the areas in one geography (the source) to another geography (the target).
Full details regarding how these concepts are applied to data within Neighbourhood Statistics can be found in the Neighbourhood Statistics Geography Policy (Pdf 600Kb).
How do I find data for Parishes or Westminster Parliamentary Constituencies - For the 2011 Census, data is only available at Parish or Westminster Parliamentary Consituency (WPC) level via the 'custom' route or the 'find statistics for an area' route.
Go to the Neighbourhood Statistics homepage
Go to the 2011 Census homepage
