Chief statistician’s update: updating the names for Lower Super Output Areas (LSOAs) in Wales

Darllenwch y dudalen hon yn Gymraeg

What are Lower Super Output Areas (LSOAs)?

LSOAs are geographical areas of similar population size used for reporting small area statistics. There are 1,917 LSOAs in Wales. Each LSOA contains between 400 and 1,200 households with a resident population between 1,000 and 3,000 people.

LSOAs were first created by the Office for National Statistics (ONS) following the 2001 Census. These geographies undergo changes at each census in response to changes in local population sizes. After a census, existing LSOAs can be merged or split to create new ones to ensure population and household thresholds are met.

Following the 2011 Census, Wales had 1,909 LSOAs, which increased to 1,917 after the 2021 Census. The majority (1,837) LSOAs were unchanged, 45 were merged and 58 split.

Why are ‘local names’ used for LSOAs in Wales?

The names of the LSOAs provided by the ONS are based on their local authority – for example Denbighshire 004E. However, these non-intuitive names made it difficult for users to link the LSOA to a recognisable area within the local authority. In 2005, the Welsh Index of Multiple Deprivation (WIMD) was produced using LSOAs for the first time and this drove the creation of ‘local names’ for the LSOAs in Wales as electoral wards had been used previously. The local names were based mostly on the electoral ward that the LSOA was part of. In the above example, Denbighshire 004E was named Rhyl West 2 as it was part of the ‘Rhyl West’ electoral ward. These names provided a clearer description of the geographical area to local decision-makers, the media and members of the public wishing to use small area statistics.

Why do we need an update to the current LSOA names in Wales?

Following a recent review of the electoral wards in Wales in 2022, the Welsh Language Commissioner, Boundary Commission for Wales and Welsh Government agreed a set of new electoral ward names in English and Welsh. This has resulted in a mismatch between the ‘local names’ for many Welsh LSOAs and the new electoral ward names. There were also 22 new LSOAs created (through the merging of existing 2011 based LSOAs) with the 2021 based census geographies, with 58 created through the splitting up of the 2011 based LSOAs. Each of these requires a new name attached to it.

How will we update the local LSOA names in Wales?

If we followed the same approach as before, we would use electoral ward names where it is possible to do so. For example if the LSOA is entirely within a ward then using the ward name for the LSOA this would be acceptable, however there are many which do not fit neatly within a single electoral ward.

We considered three options for updating the names of LSOAs in Wales:

  1. Cease the use of the local names and use the names provided by ONS.
  2. Update the names of any changed LSOAs only.
  3. Review the names of all LSOAs.

Whilst options 1 and 2 would be the simplest and quickest there are compelling reasons to fully review all the LSOAs and adopt potentially new names for each:

  • The local names have been in place for almost 20 years and are widely used, so choosing to not provide local names in future would be a backwards step.
  • Many of the existing names no longer match the electoral ward name.
  • The 2011 changes only updated new or changed LSOAs and did not review any others.
  • We can encourage a consistent naming method used across all local authorities.

How are we reviewing the names of LSOAs in Wales and what are we doing next?

Welsh Government shared an initial set of proposed names with local authorities. The next step is to address the feedback provided so far and, in particular, to agree an approach for when an LSOA covers parts of multiple wards. Local authorities and the Welsh Government will work together on mutually agreeing on the changes to the LSOA names and will consult the Welsh Language Commissioner for advice on bilingual names.

Email: data@gov.wales