Findings from our review of household estimates and projections in Wales, Scotland and Northern Ireland

Continued from the Housing, Planning and Local Services domain page…

Household estimates and projections are a key source used to inform local housing need and are therefore of high user interest. Our recent compliance checks of the household estimates and household projections produced for Wales, Scotland and Northern Ireland, found several examples of good practice which support the trustworthiness, quality, and value of the statistics and help realise cross-UK benefits. These include:

  • A planned transparent public commitment by the statistics teams in all four UK nations to coordinate the timing of the next sets of household projections (and subnational population projections) using results from the 2021 England and Wales, and Northern Ireland Censuses, and using a common 2021 base year, where possible.
  • Strong communication links between statisticians and housing need analytical teams in Wales and Scotland. Within Wales this has led to timely additional housing need analyses and the publication of a comprehensive¬†housing need publication for Wales, which directly reflects the considerable uncertainty and potential variants in the estimation of future housing need, as reflected in the variant household projection official statistics.
  • Sensitivity analyses carried out by NISRA and NRS to enhance understanding of the quality and robustness of its projections, and NISRA‚Äôs proactive collection and analysis of students‚Äô home and university addresses to ensure quality, as part of the 2021 Census.
  • Direct engagement with Welsh local authorities as part of subnational projections quality assurance and regular fora for Scottish local authorities to contribute their views on data quality and developments, to ensure projections reflect local knowledge. We also welcome that while NISRA is commissioned to produce household projections specifically to inform housing need analyses, further steps are taken to ensure the projections have value for other users.

We also identified some key areas for improvement to strengthen the quality and public value of these statistics across the UK, including:

  • The need for enhanced collaboration between the UK producers to share and use¬†the latest data, methods, and¬†improvements at the subnational level. While there are well-established arrangements for collaboration around national projections and Censuses, collaboration at the subnational household projections level is much less established. Strengthening opportunities for working together at this level will enable further sharing of knowledge that would enhance the value of the projections for users, particularly in the context of coordinated UK household projections outputs in 2023.
  • Investigate potential data quality issues in local-level data, particularly in university towns and cities with large student populations, which could lead to misleading population estimates and poor local planning or service provision decisions. We encourage the producer teams to work together with ONS to inform each other‚Äôs understanding of source data quality, and address any identified local data quality issues, ahead of future household estimates and projections being produced.
  • The use of fan-charts means that more-intelligent conversations can be had by decision makers about possible future trends. Producers should enhance presentation of uncertainty in household estimates and projections, including at a local level. For example, exploring options for interactive variants projections, fan-charts or other visuals or interactive content, to help support the appropriate interpretation of data and uncertainty, across different levels of geography.
  • Enhance relationships between statisticians and housing need analysts and provide appropriate guidance to ensure that the relative strengths, limitations, degree of uncertainty, and range of household projections variants, are suitably accounted for in the housing needs analyses, while encouraging their publication in line with the principles of the Code of Practice for Statistics.
  • Collaborate to publish a current overview of the methods used¬†to produce estimates of households and¬†dwellings in the four UK countries. This will help to improve coherence and accessibility by creating a single access point for users to understand¬†the different nations‚Äô approaches.
  • Proactively seek out opportunities to engage users about forthcoming timetables and developments, so that they are aware and have opportunities to contribute their views.

Findings of relevance to household projections for England

The findings from these reviews for the household estimates and projections produced for Wales, Scotland and Northern Ireland offer insights which also support the production and use of household projections for England, including covering some of the themes highlighted in our recent review of population statistics produced by ONS.

In particular, we note the importance of collaboration between producers of household estimates and projections across the UK in order to share best practice, and strong working relationships between those producing estimates and projections and those responsible for future housing need analysis.

Wales provides a clear example of where this works well and the potential benefits, where taking a collaborative approach has led to the production of a timely and accessible estimates of housing need publication, which includes clear guidance around what the estimates should and should not be used for and draws on different household projections variants to illustrate inherent uncertainties associated with assessing future housing need.

Looking ahead to updated household estimates and projections after the Census, we expect to see close engagement between the different producer teams, policy analysts and other users, to maximise the value of the outputs and to reflect the latest methods and quality improvements. Following our reviews, statisticians in Wales, Scotland and Northern Ireland have committed to work together to help maximise the trustworthiness, quality and value of the updated household estimates and projections, and in England we have written to ONS and MHCLG to ask for the same commitment from them.

For example, to ensure that future assessments of housing need are informed by the latest data, and reflect any new methods and quality advances, we expect that future housing need analyses produced for England will be based on ONS’s updated 2021-based household projections. MHCLG officials responsible for housing need analysis will therefore need to work closely with producer teams in ONS, to ensure that future housing need analyses are informed by a clear understanding of the strengths, limitations, and potential projection variants. And where published, these analyses should be made available transparently and informed by the principles of the Code of Practice for Statistics.

This will bring the approach taken in England in line with those already established in Wales, Scotland and Northern Ireland, which will themselves be informed by the 2021 Censuses.