What is coming up on population and migration statistics

On 23 November, we will be publishing new and updated data on population and migration. It will include population data for 2012 to 2022 and migration data for 2012 to 2023. The statistics will be published through our:

• Rebasing of mid-year population estimates following Census 2021, England and Wales bulletin for the period 2012 to 2021
• Mid-year Population estimates for England and Wales: mid-2022 bulletin
• Estimating UK international migration article for the period 2012 to 2021
• Long-term international migration, provisional: year ending June 2023 bulletin, containing estimates for 2012 to year ending June 2023.

These outputs bring together population and migration statistics to provide coherent estimates which draw on the latest available data.

The statistics for 2012 to 2021 are being updated to align with data from Census 2021. Census 2021 for England and Wales currently provides our most detailed snapshot of the population including household characteristics, employment, health, religion and international migrants. After each Census, we use this rich dataset to update our previous population and migration estimates.

However, we cannot stop with the census, as there continues to be changes; people move homes, change jobs, and some will leave the country while others will arrive. Therefore, we draw on a range of sources and increasingly aim to make use of administrative data to enhance the estimates.

The mid-year 2022 population estimates will be based on our cohort component method (see our Methodology used to produce the national population projections). Migration figures are admin-based migration estimates (ABMEs), which bring data together and estimate the likely outcome of long-term international migrants who have recently immigrated or emigrated. Our ABMEs measure EU and non-EU nationals migrating to the UK. For British nationals, we continue to use the International Passenger Survey (IPS) while we explore alternative administrative sources for this group.

We are also publishing articles to support users in understanding the estimates and our work to make improvements. These include our Reason for international migration, international students update: November 2023, our Improving international migration statistics using administrative data, and our Long-term international migration: quality assuring administrative data articles.

Our population and migration outputs are produced in line with the principles set out in the UK Statistics Authority’s (UKSA) Code of Practice for Statistics. Therefore, our priority is demonstrating trustworthiness, quality, and value in our publications.

We are continuously looking to improve the statistics on population and migration so that they reflect changes in society and technology and better meet user needs. The publications in November are ongoing improvements as part of our transformation of population and migration statistics (see our Overview of statistics transformation for more information). As we look to make greater use of administrative data we are: 

• considering how to use new data sources and methods to support more timely, inclusive and relevant estimates

• seeking to continuously improve the quality of our outputs in line with our Statistical Quality Improvement Strategy and our Data Strategy 

• undertaking further work to help users understand statistical uncertainty associated with the estimates

In December, we will publish further information on our admin-based population estimates (ABPEs) using our dynamic population model (DPM) (see our DPM, improvements to data sources methodology). This approach draws strength from a range of data sources, such as administrative and survey data. The December publication will include a methodological article to support user input into our transformation of population statistics.

The responses to our Consultation on the future of population and migration statistics in England and Wales will inform our longer-term transformation plans. Over the coming months we will be reviewing the responses we have received and sharing more details on how this will shape the future of population and migration statistics.

As we make greater use of administrative data, we should be able to publish more timely estimates with a more consistent level of quality. The first, most timely, estimates will be provisional estimates, giving an initial indicator of population or migration based on early data and assumptions about people’s migration status based on past behaviour. When more data relating to the reference period become available, these provisional estimates will then be updated with new estimates with reduced statistical uncertainty. In statistical outputs, we refer to the planned updates resulting from improvements to data or methods as revisions. This approach to revisions enables us to meet a broader set of user needs: those who benefit from an indication of changes as close to the reference period as possible and are willing to accept a higher degree of uncertainty, and those whose need for greater accuracy means they will wait for estimates with greater certainty. Our approach to revisions is guided by international best practice and is consistent with our Guide to statistical revisions.

We will be transparent about our approach to planned revisions. We will continue to engage with users to understand their needs, reflect on views provided in the Consultation and review the recommendations made in the Office for Statistics Regulation’s GDP revisions review before updating our Population and International Migration Revisions Policy in line with our transformed system.

Feedback

User needs are at the forefront of our thinking when making decisions about improvements to population and migration statistics and, as always, we value any feedback on our developments.

If you require more information about this article or would like to feedback comments, please contact pop.info@ons.gov.uk. We also invite comments on how users would like to be kept informed.

Administrative data

These are data that people have already provided to government, for example, while accessing public services. Some of these data could be re-used by the Office for National Statistics (ONS) to produce statistics about the population.

We have been using administrative data for many years. For example, annual births and deaths statistics are used, as well as NHS patient registrations, to roll forward the population estimates between censuses.

Dynamic population model

The dynamic population model (DPM) is a statistical modelling approach that uses a range of data to measure the population and population changes in a coherent way. For more information, see our DPM, improvements to data sources methodology.

Mid-year population estimates

The mid-year population estimates relate to the usually resident population on 30 June of each year. A mid-year estimate gives an indication of how many people are typically resident in a certain area over the calendar year.

Long-term international migration

Long-term international migration (LTIM) statistics estimate the flow (or movement) of migrants to and from the UK. This bulletin uses the United Nations (UN)-recommended definition of a long-term international migrant, as explained in the Recommendations on Statistics of International Migration paper (PDF, 5MB). It is defined as "a person who moves to a country other than that of his or her usual residence for a period of at least a year (12 months), so that the country of destination effectively becomes his or her new country of usual residence."

Cohort component method

Population (year x) (population at the beginning of the year):

• plus births (between years x and y) (plus births in year)
• minus deaths (between years x and y) (minus deaths in year)
• plus net-migrants (between years x and y) (plus or minus adjustment for migrants)

This equals population (year y) (gives population at the end of the year).

For more information, see our Methodology used to produce the national population projections.