Dwelling stock estimates: quality report

This statistical release presents estimates of the number of dwellings (including vacant) in Wales and each local authority by tenure.

The dwelling stock estimates are used as evidence in policy making by both central and local government. The information provides an estimate of the number of residential dwellings by each tenure type and by local authority, at the end of March each year. The data are used by the Welsh Government, local authorities and other housing organisations to help monitor trends in the overall level of Welsh housing stock, as well as any changes in its tenure distribution over time.

More generally the information is used for:

• monitoring housing trends
• policy development
• advice to Cabinet Secretaries and Ministers
• informing debate in the Senedd Cymru and beyond 
• geographic profiling, comparisons and benchmarking

There are also a variety of further users of these statistics including national and local government, other government departments, researchers, academics and students.

Estimates of the total number of dwellings are based on data from the population censuses, the latest of which was in March 2021. Estimates from the censuses are updated annually to take account of new house building and demolitions. 

2022-23 represents the financial year April 2022 to March 2023.

Figure 1: Calculation of dwelling stock estimates, as at 31 March 2023

Image

Description of Figure 1: An infographic showing the formula used to calculate the dwelling stock estimates as at 31 March 2023. 

The breakdown of dwelling stock estimates by tenure is estimated from local authority returns, registered social landlord returns and estimates from the Annual population survey (APS).

Figure 2: Calculation of private sector stock and tenure split, as at 31 March 2023

Image

Description of Figure 2: An infographic showing the formula used to calculate the private sector, privately rented and owner-occupied stock estimates as at 31 March 2023.

Methodological improvement

In 2018-19 we carried out a review of the methodology used to calculate the tenure split of private sector stock. As a result of this review, we introduced a number of methodological improvements:

• switched to using the APS household dataset (as opposed to the APS person dataset)
• applied the APS proportion of privately rented dwellings to the estimate of private sector stock (as opposed to all dwelling stock)
• introduced a three-year smoothing technique to decrease volatility in the APS estimates.

Please refer to Dwelling Stock Estimates, as at 31 March 2019 for full details of the methodological improvements.

Strengths

• The information is processed and published frequently and in an ordered manner to enable users to see the statistics when they are current and of greatest interest. 
• Data is obtained directly from housing providers and undergoes rigorous quality assurance. 
• Detailed statistics are provided via our StatsWales website at local authority level

Limitations

• Due to the coronavirus (COVID-19) pandemic, data for registered social landlord stock in 2019-20 has been estimated based on previous trends. 
• The information on new house building used in the annual dwelling stock estimates is based on the reports of local authority building inspectors and the National House Building Council (NHBC), which is a private approved inspector (PAI). It does not include information from other private approved inspectors. 
• Currently, data from the Annual population survey (APS) is used to calculate an estimate of the number and proportion of private rented dwellings. The APS provides estimates for the private rental sector but it only covers occupied dwellings, therefore no account is taken of vacancy rates in producing the tenure split. The APS is a household survey and therefore also has an associated level of uncertainty.

Welsh housing statistics adhere to the Welsh Government’s Statistical Quality Management Strategy, and this is in line with the European Statistical System’s six dimensions of quality, as listed in Principle 4 of the Code of Practice for Statistics. Further detail on how these are adhered to can be found in the housing statistics quality report  which covers the general principles and processes leading up to the production of our housing statistics. The report covers various topics including definitions, coverage, timeliness, relevance and comparability.

The closeness between an estimated result and the (unknown) true value. 

Data sources

This release draws on information from a range of data sources in order to compile a coherent set of statistics on the total number of dwellings and the tenure profile of the stock. The statistical sources used to calculate dwelling stock estimates include:

• Census 2021 (Office for National Statistics (ONS)), Census 2011 (ONS) and Census 2001 (ONS) (Office for National Statistics). Data on the number of dwellings was published March 2023.
• 2022-23 new house building completions (StatsWales) (Welsh Government). Latest data was published March 2024. 
• 2022-23 housing demolitions (StatsWales) (Welsh Government). Latest data was published March 2024. 
• 2022-23 local authority and registered social landlord stock (StatsWales) (Welsh Government). Latest data was published September 2023. 
• 2022 Annual Population Survey (ONS). APS person data was published April 2024. The household dataset (calculated from the person dataset) is published at a later date. The data is from the calendar year 2022.

The proportion of social housing stock managed by registered social landlords will have been influenced by the large-scale voluntary transfers of local authority stock. All transfers covered 100% of the local authority housing stock. A list of the large-scale voluntary transfers of local authority stock and dates of transfer to registered social landlords are shown below.

Description of Table 1: A table showing that the large scale voluntary transfer of local authority stock took place between September 2003 and March 2011. 

Typically, there is a degree of uncertainty surrounding the tenure split of private sector stock owing to the nature of the APS dataset. Therefore, estimates in this release have been rounded to the nearest 100. 

In order to communicate uncertainty, confidence intervals have been calculated for estimates, as at 31 March 2023 (based on three-year smoothing).

Description of Table 2: A table highlighting that there is a degree of uncertainty surrounding the tenure split of private sector stock. The confidence intervals are relatively narrow and equal for both owner-occupied and privately rented tenures. 

To reduce volatility in the APS estimates used to calculate the private sector split, a smoothing technique was introduced in 2019. 

Due to the nature of the APS household dataset and to improve the timeliness of data, the previous year’s APS data is used to calculate the latest years figures. This means that for the latest two years of data, the same privately rented dwelling proportion is used to calculate the tenure split for the private sector. The two latest years are smoothed as follows: 

0.75* latest available APS data + 0.25 * previous year APS data.

For all other estimates, as at 31 March each year, APS estimates have been smoothed as follows: 

0.25 * previous year APS data + 0.5 * current year APS data + 0.25* following year APS data. For example, estimates at 31 March 2021 have been smoothed using 0.25 * 2020 APS data + 0.5 * 2021 APS data + 0.25* 2022 APS data

In applying this three-year smoothing technique, estimates, as at 31 March 2021 and 2022, have been revised to take into account recently published 2022 APS data. Estimates, as at 31 March 2023, are currently provisional and will be subject to revision when 2023 APS data becomes available.

Revisions

Small revisions are made annually to estimates of owner-occupied and privately rented stock as more recent APS data is made available. For 2022, the revised estimate of owner-occupied dwellings in Wales decreased by 4,500 and the number of privately rented dwellings increased by 4,500. 

Revisions can arise from events such as late returns from a local authority or RSL or when a data supplier notifies the Welsh Government that they have submitted incorrect information and resubmits this. Occasionally, revisions can occur due to errors in our statistical processes. In all of these cases, a judgement is made as to whether the change is significant enough to publish a revised statistical release. 

Where changes are not deemed to be significant, i.e. minor changes, these will be updated in the following year’s statistical release. However, minor amendments to the figures may be reflected in the StatsWales tables prior to that next release.

Revised data is marked with an (r) in the statistical release

We follow the Welsh Government’s statistical revisions policy.

Accessibility and clarity 

Accessibility is the ease with which users are able to access the data, also reflecting the format(s) in which the data are available and the availability of supporting information. Clarity refers to the quality and sufficiency of the metadata, illustrations and accompanying advice.

Dwelling stock estimate statistics for Wales are published in an accessible, orderly, pre-announced manner on the Welsh Government website at 9:30am on the day of publication. 

We aim to inform known key users of the publication of the statistics when they are published. An e-mail is circulated to the Housing Information Group. 

We aim to use plain English in our outputs and all outputs adhere to the Welsh Government accessibility policy. Furthermore, all our headlines are published in Welsh and English. 

Further information regarding the statistics can be obtained by contacting the relevant staff detailed on the release or via stats.housing@gov.wales. 

A full set of data on dwelling stock estimates in Wales, including information by individual local authority is available to download from our StatsWales website. We have also developed an interactive dashboard where you can view housing supply statistics at a regional and national level.

Coherence

Coherence is the degree to which data that are derived from different sources or methods, but which refer to the same phenomenon, are similar.

There are several alternative sources of data on total dwelling stock in Wales, including the council tax system. The Welsh Government collects and publishes annual information on dwellings under the council tax system which is provided by the 22 Welsh local authorities. 

The Welsh Government also collects information on social housing stock which is based on annual stock returns collected from the 22 Welsh local authorities and all Welsh registered social landlords. The total local authority and registered social landlord stock figures published in the social housing stock release will differ slightly from the figures shown in this release. This release assumes 3 bed spaces of a non-self-contained unit is equivalent to 1 dwelling. 

New house building completions are one of the most important factors affecting the annual change in the size of the dwelling stock. The Welsh Government publishes a quarterly headline and an annual release covering new build starts and completions based on the reports of local authority building inspectors and the National House Building Council (NHBC) which is a private approved inspector (PAI). 

The number of dwellings demolished is also another factor affecting the annual change in the total dwelling stock. Data on demolitions is collected annually by the Welsh Government from all 22 local authorities in Wales. The statistics on demolitions cover all demolitions of residential dwellings of which the local authority is aware. They also include dwellings demolished which are to be re-built afterwards.

Annual national and subnational statistics on the dwelling stock are available for each of the four UK countries. For England, Scotland and Wales these are also available with a breakdown of the number of owner-occupied and privately rented dwellings, as well as social housing down to local authority level. Statistics on the breakdown of owner-occupied and privately rented dwellings by local government district are not yet available for Northern Ireland. 

These statistics are produced using different methods and data sources, although the concepts measured are the same.

England

The Ministry of Housing, Communities & Local Government (MHCLG) produces accredited official statistics on the number of dwellings by tenure at the national, regional and local authority level in England. MHCLG use a similar method used for the Welsh estimates, by taking the dwelling count from census data as baseline. The count is projected forward using information on net annual changes to the dwelling stock (census + net additions), which are also collected and published by the MHCLG in the net additional dwellings statistics. 

At the national and regional level, these statistics contain estimates of the number of dwellings in the private sector (owner-occupied and privately rented) and the number of dwellings in social housing. MHCLG does not produce a breakdown of the number of owner-occupied and privately rented dwellings within the private sector at the local authority level. The ONS uses data from the APS to provide an estimate of the number of owner-occupied and privately rented dwellings at local authority level by applying this breakdown to the estimate of the total number of privately-owned dwellings. All statistics for England are adjusted to account for regional variations in the proportion of vacant dwellings by tenure.

Scotland

The Scottish Government publish summary information on the estimated stock of dwellings by tenure in Scotland in the annual key information and summary tables.

For Scotland, the breakdown of owner-occupied and privately rented dwellings from the Scottish Household Survey are applied to the estimates of privately-owned dwelling stock. This breakdown is achieved by comparing total dwelling figures, provided by the National Records of Scotland, with social housing stock figures, as held by local authorities and housing associations.

Northern Ireland

Northern Ireland, like Scotland, uses administrative data. Land & Property Services (LPS) provide a valuation for all properties in Northern Ireland which are subject to rates. Housing Stock is defined as a count of properties which are valued as domestic or mixed for the purposes of rating and includes both social sector and private sector dwellings in the Valuation List. Housing Stock information is available for Northern Ireland and each of the Local Government Districts within NI on a comparable basis from 2008 to 2024.

In regard to the social rented sector, the Northern Ireland Housing Executive (NIHE) can provide data on NIHE stock, while information on social housing stock owned by Housing Associations can be provided by the NI Federation of Housing Associations (NIFHA) or DfC’s Housing Regulation Branch, upon request.

Tenure estimates, including those for the private rented sector in NI, are sourced from survey data, for example, the Continuous Household Survey and the NI House Conditions Survey.

We always welcome feedback on any of our statistics. Please contact us via email: stats.housing@gov.wales

Produced by Knowledge and Analytical Services, Welsh Government