National population projections, subnational population projections and household projections for England – future plans:  June 2021

In our 2018-based subnational population projections (SNPPs) and household projections (HHPs) we stated a proposal not to publish 2020-based projections. We can now confirm that following feedback from our stakeholder engagement activities we will not be producing 2020-based SNPPs and HHPs. After carefully reviewing and considering all user feedback and requirements, we plan for the next set of SNPPs and HHPs to be 2021-based. These projections will use Census 2021 data when this becomes available. We plan for 2021-based projections to be published in 2023.

Our update in April 2021 summarised user feedback received (in response to the user engagement exercise we ran in autumn 2020) and explained our decision to produce "2020-based interim national population projections". The production of these has begun and they will be published in December 2021.

The following sections provide more detail on our plans for population and HHPs including:

• the background and wider context to our original proposal (outlined in our 2018-based projections) for 2021-based SNPPs and HHPs

• an update on the "2020-based interim national population projections" and our plans for the components of the release following the announcement in our user engagement report, published April 2021

• plans for 2021-based national population projections, SNPPs and the HHPs in response to user feedback

• an overview of the national population projections, SNPPs and HHPs, and related links

In our 2018-based population and household projection releases, we outlined a proposal not to produce 2020-based projections. In following our regular two-year cycle of projections releases, 2020-based subnational population projections (SNPPs) and household projections (HHPs) would have been published in spring and summer 2022. We outlined this proposal because SNPPs and HHPs would have been published around the same time as the provisional first release of Census 2021 results, which are expected in spring 2022 and would not be based upon the census data itself.

We therefore proposed not to produce this round of SNPPs and HHPs and that the next round of these projections would be 2021-based. Confirming our approach of not producing 2020-based SNPPs and HHPs will enable our planned next set of SNPPs and HHPs to use the updated base population that the Census 2021 results will offer and a revised back-series of earlier years of input data.

In April 2021 we announced plans to produce 2020-based interim national population projections (NPPs) consisting of a principal projection only, in order to meet core user needs found through our user engagement exercise held in autumn 2020. We plan to publish these in December 2021. The release will be produced using an updated set of demographic assumptions and titled "2020-based interim national population projections".

As we detailed in our April 2021 publication, user feedback on the potential for a shorter release was mixed. While some said they would be satisfied with a scaled back release, others indicated that this would not meet their needs and risked not providing the level of support they needed. After considering this feedback, we propose that the publication of the 2020-based interim NPPs will consist of projections data and the following:

• a statistical bulletin 

• a blog which will provide a summary of what we have produced, and why and how it should be used  

• an overview of how the assumptions were developed 

• a summary of the assumptions for fertility, mortality, and migration 

• a methodology document

• Quality and Methodology Information (QMI)

The publication of the 2020-based interim NPPs in December 2021 will reflect our innovative use of alternative data sources (for example, modelled estimates of international migration in our 2020 mid-year population estimates; the base year of the projections). The improvements in our data sources outlined in our blog, meeting the challenges in population estimation, published in May 2021, highlight what we have been doing to adapt our methods particularly in light of the coronavirus (COVID-19) pandemic. These include our plans for the transformed migration statistics methodology based on further administrative data. The above developments are designed to better reflect the population changes that have taken place over the course of the coronavirus pandemic and provide the best possible national picture for decision makers.

Feedback through our user engagement exercise in autumn 2020, and more widely on household projections (HHPs) - which were not part of the above user engagement exercise - has helped us to confirm a final decision not to publish 2020-based subnational population projections (SNPPs) or HHPs and to break the two-year cycle of production. Timing of 2020-based releases for these outputs would have been very close to a provisional release of Census 2021 data. Furthermore, this approach also allows us to better understand the effects of the coronavirus (COVID-19) pandemic and for these to be more fully included in the projections through using updated input data.

The National Population Projections Committee comprising the Office for National Statistics (ONS), National Records of Scotland (NRS), Northern Ireland Statistics and Research Agency (NISRA) and the Welsh Government currently propose that, following the publication of the "2020-based interim national population projections" in December 2021, the next round of national population projections (NPPs) will be 2021-based. These will include Census 2021 data for England, Wales, and Northern Ireland (the latest mid-year population estimates for Scotland rolled forward from the 2011 Census), and an updated set of demographic assumptions and projection variants. We plan to publish these in early 2023, although at this stage, this is not a definitive policy and we cannot be certain of exact timings.

In spring and summer 2023 the release of 2021-based SNPPs (England) and 2021-based HHPs (England) are planned to follow the 2021-based NPPs release. After that, our current proposal is that all future projections will revert to our previous biennial cycle. As such, the 2023-based NPPs would be expected to be published in late 2024 and the SNPPs (England) and HHPs (England) would then follow in spring and summer 2025. Confirmation of this as our definitive approach and more precise timings will be announced closer to the planned 2023-based projections cycle.

Announcements on future timescales for the SNPPs and HHPs from other parts of the UK will be made separately by NRS, NISRA and the Welsh Government. User feedback from the recent engagement exercise in autumn 2020 as well as local user engagements, which may take place in each country, will inform these timescales.

We will support users in their use of our projections and welcome feedback on the projections and future requirements, particularly when we begin to integrate Census 2021 data into our updates. Please let us know your thoughts by emailing pop.info@ons.gov.uk.

Further updates on the timing of future projections will be communicated in our quarterly Population and Migration Statistics newsletter. To sign up to this, please contact us at pop.info@ons.gov.uk.

National population projections (NPPs) are produced by age and sex for the UK and its constituent countries and are usually published every two years. The National Statistician and the Registrars General for Scotland and Northern Ireland commission the Office for National Statistics (ONS) to prepare and produce NPPs on their behalf. The projections are based on the latest mid-year population estimates together with assumptions of future levels of fertility, mortality, and migration. The NPPs are broken down by sex and single-year of age and usually cover the following 100 years, although because of the uncertainty of longer-term projections the first 25 years are covered in our bulletins.

The primary purpose of the projections is to provide information on potential future population levels. They are used as a common framework for national planning in several different fields. The NPPs are published for each of the four UK nations and the ONS works closely with our partners in the devolved administrations, including discussing appropriate methods and data sources. We do this through NPP committee meetings, as well as ongoing collaboration.

Subnational population projections (SNPPs) provide statistics on the potential future size and age structure of the population in England at region, county, local authority, clinical commissioning group and NHS England region levels. They are used as a common framework for informing local-level policy and planning as they are produced on a consistent basis. SNPPs are produced by the appropriate organisation for each part of the UK: the ONS for England, the Welsh Government for Wales, the National Records of Scotland (NRS) for Scotland, and the Northern Ireland Statistics and Research Agency (NISRA) for Northern Ireland. These projections are usually produced every two or three years (depending on the production cycle) for local authority districts and similar administrative areas. The SNPPs project the population for each year of a 25-year period from the base year. SNPPs are also used in the production of the household projections for local authorities.

Household projections (HHPs) provide statistics on the potential future number of households at region, county, and local authority level for England and by household type at region and local authority level for England. HHPs are produced by the appropriate organisation for each part of the UK: the ONS for England, the Welsh Government for Wales, the National Records of Scotland (NRS) for Scotland and the Northern Ireland Statistics and Research Agency (NISRA) for Northern Ireland. They show the household numbers that would result if the assumptions based in previous demographic trends in population and household formation were to be realised in practice.

Similarly to the subnational population projections they are used as a common framework for informing local-level policy and planning and are a starting point for calculating future housing needs. The household population projections usually follow the publication of the SNPPs every two or three years (depending on the production cycle) for local authority districts and similar administrative areas and project the population for each year of a 25-year period from the base year.