Migration Statistics Quarterly Report: November 2019

A summary of the latest official long-term international migration statistics for the UK for the year ending June 2019 published by the Office for National Statistics (ONS). Data from the Home Office, the Department for Work and Pensions (DWP) and the Higher Education Statistics Agency (HESA) are also included.

This is the latest release. View previous releases

Contact:
Email Ann Blake

Release date:
28 November 2019

Next release:
27 February 2020

2. Feedback on the development of migration statistics

Making the best possible assessment of migration using all available data sources

We are transforming our migration statistics, making use of all available data to provide a richer and deeper understanding of migration. Since July 2018, we have been integrating outcomes from this work into the Migration Statistics Quarterly Report (MSQR).

We published our first set of preliminary adjustments in the August 2019 MSQR and have applied the same preliminary adjustments to the headline measures in this report to provide our best possible assessment of migration trends. The figures and trends in this report are therefore based on our adjusted estimates where available, which have so far been applied until 2016 for EU migration and up to the latest year for non-EU migration. Our best assessment of EU net migration since 2016 remains our International Passenger Survey (IPS)-based estimates.

As other new data sources become available, we will continue to refine our adjustments further and reflect this in our migration statistics. We plan to develop the preliminary adjustments in the February and May 2020 MSQRs and will inform users of these when possible. We expect final adjustments to be developed by summer 2020. While we go through this transformation journey, the MSQR has been reclassified as Experimental Statistics to support this period of development and innovation to meet the public good.

We would like your feedback

The Office for National Statistics (ONS) is seeking user feedback during this period of development so we can better understand your needs. Please contact us with your views on the methods we are developing along with the detail you require and how this is presented. Please email any feedback to pop.info@ons.gov.uk.

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3. Main points

To fully understand long-term international migration trends, we need to consider all available data sources. Throughout this report, we provide our best assessment of migration trends given data availability.

In the year ending June 2019, long-term international migration continued to add to the UK population, as an estimated 212,000 more people moved to the UK with an intention to stay for 12 months or more than left the UK (net migration). Over the year, 609,000 people moved to the UK (immigration) and 397,000 people left the UK (emigration).

Long-term net migration, immigration and emigration have remained broadly stable since the end of 2016.

Since 2016, there has been a decrease in immigration for work; over the same period, immigration for study has been gradually increasing.

There are different patterns for EU and non-EU migration (note from March 2016, no preliminary adjustments were applied to EU migration estimates; as such, we have made our best assessment based on all the available evidence):

  • EU net migration has fallen since 2016, although more EU citizens arrive long-term than leave; this is because of a gradual increase in EU citizens leaving as well as a decrease in those coming to the UK over the same time period.

  • The fall in immigration for work has mainly been because of a decrease in EU citizens coming to the UK looking for work, particularly those from the EU8; for non-EU citizens, all available data sources have shown increases in the numbers coming to the UK for work since 2014.

  • Non-EU net migration has gradually increased since 2013, as immigration has risen and emigration remained broadly stable for this group.

  • The rise in non-EU immigration is mainly because of a gradual increase in those coming to the UK for formal study, a trend reflected in all available data sources with sponsored study visa applications for universities at the highest level on record.

In the year ending September 2019, the latest available Home Office statistics also published today show that the UK offered protection -- in the form of grants of asylum, humanitarian protection, alternative forms of leave and resettlement -- to 19,480 people (up 28% compared with the previous year).

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Long-term international migration data from the Office for National Statistics (ONS) are largely based on a survey. It is not possible to survey all people coming to and leaving the UK, so these statistics are estimates based on a sample, not precise figures. Where possible, to assess migration trends we use all available data sources and review the longer time series.

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4. Statistician’s comment

Commenting on today’s migration figures, an Office for National Statistics (ONS) spokesperson said:

“Our best assessment using all data sources is that long-term immigration, emigration and net migration have remained broadly stable since the end of 2016. However, we have seen different patterns for EU and non-EU citizens.

“While there are still more EU citizens moving to the UK than leaving, EU net migration has fallen since 2016, driven by fewer EU arrivals for work. In contrast, non-EU net migration has gradually increased for the past six years, largely as more non-EU citizens came to study.”

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5. Migration continues to add to the population of the UK

In the year ending June 2019, long-term international migration continued to add to the UK population as an estimated 212,000 more people came to the UK with an intention to stay 12 months or more than left the UK (net migration). Over the last year, 609,000 people moved to the UK (immigration) and 397,000 people left the UK (emigration).

Since the end of 2016, long-term net migration, immigration and emigration have remained broadly stable.

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The findings in this section are based on the preliminary adjusted estimates for the years in which they are available. Otherwise, the unadjusted Long-Term International Migration (LTIM) estimates remain our best available estimates. We will continue to develop our adjustment approach in our future reports, especially as more data become available.

Figure 1: Long-term immigration, emigration and net migration have remained broadly stable since the end of 2016

Long-term international migration, UK, year ending December 2009 to year ending June 2019

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Source: Office for National Statistics – Long-Term International Migration (LTIM), LTIM with preliminary adjustments based on Department for Work and Pensions and Home Office data

Notes:

  1. The data in the charts represent our best available estimates. Different types of lines have been used to represent where adjustments have and have not been applied. Where no preliminary adjustment is applicable, the line remains solid. Where a preliminary adjustment is applicable, the solid lines indicate that a preliminary adjustment has been applied, and the dashed lines indicate that a preliminary adjustment cannot yet be applied because of data availability.
  2. Preliminary adjusted estimates for EU8 citizens have been produced for the year ending June 2009 to the year ending March 2016, and preliminary adjusted estimates for non-EU students have been produced for the year ending December 2012 to the year ending June 2019.
  3. Confidence intervals for the unadjusted estimates are not shown in the chart but are available in the accompanying dataset.
  4. Confidence intervals for the preliminary adjusted estimates are not yet available. This does not mean that the estimates are more certain. As we refine our methods, we will develop our approach for displaying uncertainty around estimates based on multiple data sources.
  5. YE equals year ending.

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6. There are different patterns for EU and non-EU migration over time

While overall migration levels have remained broadly stable since the end of 2016, patterns for EU and non-EU citizens have followed different trends. EU net migration has fallen following peak levels in 2015 and 2016, while non-EU net migration has gradually increased since 2013 (Figure 2). For both EU and non-EU citizens, more come to the UK than leave the UK and they therefore continue to add to the UK population.

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The findings in this section are based on the preliminary adjusted estimates for the years in which they are available. Otherwise, the Long-Term International Migration (LTIM) estimates remain our best available estimates. We will continue to develop our adjustment approach in our future reports.

Figure 2: Non-EU net migration has increased since 2013, while EU net migration has decreased since 2016

Net migration by citizenship, UK, year ending December 2009 to year ending June 2019

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Source: Office for National Statistics – Long-Term International Migration (LTIM), LTIM with preliminary adjustments based on Department for Work and Pensions and Home Office data

Notes:

  1. The data in the charts represent our best available estimates. Different types of lines have been used to represent where adjustments have and have not been applied. Where no preliminary adjustment is applicable, the line remains solid. Where a preliminary adjustment is applicable, the solid lines indicate that a preliminary adjustment has been applied, and the dashed lines indicate that a preliminary adjustment cannot yet be applied because of data availability.
  2. Preliminary adjusted estimates for EU8 citizens have been produced for the year ending June 2009 to the year ending March 2016 and preliminary adjusted estimates for non-EU students have been produced for the year ending December 2012 to the year ending June 2019.
  3. Confidence intervals for the unadjusted estimates are not shown in the chart but are available in the accompanying dataset.
  4. Confidence intervals for the preliminary adjusted estimates are not yet available. This does not mean that the estimates are more certain. As we refine our methods, we will develop our approach for displaying uncertainty around estimates based on multiple data sources.
  5. YE equals year ending.

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While the international migration of EU and non-EU citizens continues to add to the UK population, the long-term trend for British citizens is that more leave the UK than return to the UK (Table 1).

Decisions to migrate are complex, and a person’s decision to move to or from the UK will always be influenced by a range of social and economic factors.

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We do not recommend users make comparisons year-on-year; instead, we recommend users look at the broader evidence and longer time series, which allow a better assessment of trends. See Chart 1 TS for trends.

EU net migration has fallen since 2016

Following peak levels of over 200,000 in 2015 and early 2016, EU net migration has declined and now stands at 48,000 in the year ending June 2019. This is largely because of a fall in EU immigration, which is at its lowest level since the year ending March 2013 (Figure 3).

Since 2015, EU emigration has increased but remained broadly stable in the last two years. Despite these trends, there are still more EU citizens moving to the UK to stay for 12 months or more than are leaving the UK.

Figure 3: EU net migration has fallen since 2016, but more EU citizens move to the UK than leave the UK

EU long-term international migration, UK, year ending December 2009 to year ending June 2019

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Source: Office for National Statistics – Long-Term International Migration (LTIM), LTIM with preliminary adjustments based on Department for Work and Pensions and Home Office data

Notes:

  1. The data in the charts represent our best available estimates. Different types of lines have been used to represent where adjustments have and have not been applied. Where no preliminary adjustment is applicable, the line remains solid. Where a preliminary adjustment is applicable, the solid lines indicate that a preliminary adjustment has been applied, and the dashed lines indicate that a preliminary adjustment cannot yet be applied because of data availability.
  2. Preliminary adjusted estimates for EU8 citizens have been produced for the year ending June 2009 to the year ending March 2016.
  3. Confidence intervals for the unadjusted estimates are not shown in the chart but are available in the accompanying dataset.
  4. Confidence intervals for the preliminary adjusted estimates are not yet available. This does not mean that the estimates are more certain. As we refine our methods, we will develop our approach for displaying uncertainty around estimates based on multiple data sources.
  5. YE equals year ending.

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The decline in EU net migration over the last few years is a trend that has been seen for all EU groups. The largest decline has been seen in EU8 citizens – those from Central and Eastern European countries who joined the EU in 2004 (Figure 4). As noted, preliminary adjustments have only been applied until the year ending March 2016. It is possible that once an adjustment is applied, net migration among the EU8 group could change.

Figure 4: The fall in EU net migration over the last few years is a trend that has been seen among all EU groups

Net migration by EU group, UK, year ending December 2009 to year ending June 2019

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Source: Office for National Statistics – Long-Term International Migration (LTIM), LTIM with preliminary adjustments based on Department for Work and Pensions and Home Office data

Notes:

  1. The data in the charts represent our best available estimates. Different types of lines have been used to represent where adjustments have and have not been applied. Where no preliminary adjustment is applicable, the line remains solid. Where a preliminary adjustment is applicable, the solid lines indicate that a preliminary adjustment has been applied, and the dashed line indicates that a preliminary adjustment cannot yet be applied because of data availability.
  2. Preliminary adjusted estimates for EU8 citizens have been produced for the year ending June 2009 to the year ending March 2016.
  3. Confidence intervals for the unadjusted estimates are not shown in the chart but are available in the accompanying dataset.
  4. Confidence intervals for the preliminary adjusted estimates are not yet available. This does not mean that the estimates are more certain. As we refine our methods, we will develop our approach for displaying uncertainty around estimates based on multiple data sources.
  5. YE equals year ending.

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Non-EU net migration has gradually increased since 2013

An estimated 229,000 more non-EU citizens moved to the UK than left in the year ending June 2019. This has gradually increased since 2013 largely because of a rise in non-EU immigration, while emigration has remained broadly stable (Figure 5).

Figure 5: Non-EU net migration has gradually increased since 2013, mainly driven by a rise in those coming to the UK

Non-EU long-term international migration, UK, year ending December 2009 to year ending June 2019

Embed code

Source: Office for National Statistics – Long-Term International Migration (LTIM), LTIM with preliminary adjustments based on Department for Work and Pensions and Home Office data

Notes:

  1. The data in the charts represent our best available estimates. Different types of lines have been used to represent where adjustments have and have not been applied. Where no preliminary adjustment is applicable, the line remains solid. Where a preliminary adjustment is applicable, the solid lines indicate that a preliminary adjustment has been applied, and the dashed lines indicate that a preliminary adjustment cannot yet be applied because of data availability.
  2. Preliminary adjusted estimates for non-EU students have been produced for the year ending December 2012 to the year ending June 2019.
  3. Confidence intervals for the unadjusted estimates are not shown in the chart but are available in the accompanying dataset.
  4. Confidence intervals for the preliminary adjusted estimates are not yet available. This does not mean that the estimates are more certain. As we refine our methods, we will develop our approach for displaying uncertainty around estimates based on multiple data sources.
  5. YE equals year ending.

Download the data

The increases in non-EU immigration have mainly been driven by a rise in the number of Asian citizens coming to the UK, now at 243,000 in the year ending June 2019. Home Office visa data show that many of these are likely to be Chinese and Indian nationals.

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7. Work and study remain the most common reasons to move to the UK

While remaining the two most common reasons to move to the UK, there have been different patterns in the trends for work and study (Figure 6).

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Preliminary adjustments are not available for estimates of migration by reason for visit. The Long-Term International Migration (LTIM) and International Passenger Survey (IPS) estimates therefore remain our best available estimates. We will continue to develop our adjustment approach in our future reports.

Immigration for work has fallen but remains the most common reason for EU citizens moving to the UK

Immigration for work-related reasons has fallen since the year ending June 2016 and can largely be accounted for by a decrease in EU citizens moving to the UK for work. Following a peak of 190,000 in the year ending June 2016, the number of EU citizens arriving for work has fallen to 90,000, the lowest level since 2012. This fall in work-related immigration was seen among all EU groups (EU15, EU8 and EU2).

Since the year ending June 2016, there has been a decline in the number of people coming to the UK looking for work, which largely accounts for the recent overall fall in work-related immigration. This is mainly because of a fall in the number of EU citizens coming to the UK looking for work, now at 22,000 in the year ending June 2019 compared with a peak of 82,000 three years earlier.

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Not all data sources are directly comparable. Users should be aware of this before drawing conclusions.

Foreign citizens require a National Insurance number (NINo) to work in the UK, and NINo registration data can provide another view of work-related immigration. Following a recent peak in 2015, the total number of EU NINo registrations have been falling, in line with the fall seen in the IPS data (Figure 7).

For EU citizens, the latest available data show that there were 457,000 NINo registrations in the year ending September 2019. It is important to remember that NINo registrations data are for all NINo registrations regardless of length of stay or date of arrival. They will therefore include a large number of short-term migrants and people who may have been in the country for a while before registering. The recent rise seen in NINo allocations is likely to reflect the processing of pending applications and increased operational activity resulting from the opening of two new processing centres.

All available data sources show an increase in non-EU citizens coming to the UK for work

Following an increase between 2013 and 2017, non-EU immigration for work has remained broadly stable over the last two years. However, there have been different patterns for those arriving with a definite job and those coming to the UK looking for work.

The number of non-EU citizens arriving for a definite job has increased since 2013, now at 74,000 in the year ending June 2019. This has been driven by an increase in Asian citizens arriving for a definite job – the number has more than doubled since the year ending June 2017, to 53,000.

Looking at all the available sources, by comparing the IPS with work visas and NINo registrations, we can see that all sources have shown increases in the number of non-EU citizens coming to the UK for work since 2014 (Figure 8).

Latest available data show that the number of work-related visas (including short-term or temporary work) granted in the year ending September 2019 was 189,459, its highest level since the year ending March 2008. The majority (59%) of these were for Tier 2 (Skilled) work visas, which increased by 12% to 111,035 in the latest year, following relatively stable levels between 2015 and 2018. The number of Tier 2 visas has been rising steadily since July 2018, when doctors and nurses were removed from the Tier 2 cap.

In the year ending September 2019 (latest data available), there were 293,000 NINo registrations from non-EU nationals, an increase of 50% on the previous year. Again, the recent rise seen in NINo allocations is likely to reflect the processing of pending applications and increased operational activity resulting from the opening of two new processing centres.

Home Office visa data and NINo registrations are consistent with trends in the IPS showing an increase in Asian citizens arriving in the UK for work. Since the year ending June 2013, the number of long-term work visas granted to Asian nationals increased from 18,584 to 43,013 in the year ending June 2019. Over the same time period, there was an increase of 56% in NINo registrations for Asian nationals, to 145,000 in the year ending June 2019.

EU and non-EU nationals working in the UK labour market

The Office for National Statistics (ONS) produces estimates of the labour market activity of the resident population in the UK by nationality and country of birth.

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The number of migrants working in the UK is not a measure of how many people migrate to work. Our latest report into the coherence of migration data sources discusses the differences in what survey sources tell us about migration flows. The LTIM and IPS estimates are our best available estimates of migration flows for work-related reasons. We will continue to develop our adjustment approach in our future reports.

For the period July to September 2019, the latest estimates from the Labour Force Survey (LFS) show that there were an estimated 2.24 million EU nationals working in the UK and an estimated 1.35 million non-EU nationals working in the UK.

Looking over the longer time series, since 2009 the number of EU nationals working in the UK has generally increased, while the number of non-EU nationals working in the UK has remained broadly stable.

Immigration for study is the most common reason for non-EU citizens moving to the UK and has gradually increased since 2016

Following a gradual increase since 2016, the overall number of people estimated to arrive in the UK intending to stay for a year or more for formal study was 212,000 in the year ending June 2019. Returning to levels last seen in 2011, this increase in immigration has largely been driven by a rise in Asian citizens coming to the UK for formal study, at 124,000 in the year ending June 2019.

As has been the long-term trend, formal study remains the most common reason for non-EU citizens coming to the UK, at 157,000 in the year ending June 2019.

Latest available Home Office visa data in the year ending September 2019 showed the number of Tier 4 (Sponsored Study) visas granted was 276,889, its highest level since 2011. Over half of these were for Chinese or Indian nationals (43% and 11% respectively). The majority (86%) of sponsored study visa applications in the year ending September 2019 were to study at higher education (university) institutions, and the number of non-EEA nationals arriving at universities was the highest level on record. Since the year ending September 2011, the number of Tier 4 visa applications for the further education sector fell from 100,371 to 13,223 in the latest year.

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Not all data sources are directly comparable. Users should be aware of this before drawing conclusions.

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8. The UK granted asylum, alternative forms of leave or resettlement to 19,480 people in the year ending September 2019

In the year ending September 2019, the latest available Home Office data show that the total number of people granted protection (19,480) comprised:

  • 11,596 grants of asylum (up 68%), with notable increases in grants to Iranian (up 1,348), Sudanese (up 890) and Eritrean nationals (up 839)

  • 1,099 grants of Humanitarian Protection (up 3%), over half (622) of which were granted to Libyan nationals

  • 1,179 grants of an alternative form of leave (down 12%)

  • 5,606 people were provided protection under resettlement schemes (down 6%), mainly Syrian nationals granted under the Vulnerable Persons Resettlement Scheme

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9. Migration data released today

Publications released on the same day that are related to this report include:

Provisional Long-Term International Migration (LTIM) estimates
Dataset | Released 28 November 2019
Estimates with confidence intervals for the year ending June 2019 are available. These include data on:

  • immigration, emigration and net migration by citizenship over time in Table 1 and Chart 1TS

  • immigration and emigration by reason for migration in Table 2 and Charts 2a and 2b

  • immigration and emigration by reason for migration and citizenship in Table 3 and Charts 3a and 3b

Preliminary adjusted estimates are available in this dataset and have only been applied to LTIM estimates. The International Passenger Survey (IPS) estimates in Table 3 and Table 4 have not been adjusted.

International Passenger Survey (IPS), estimates by individual quarter
Dataset | Released 28 November 2019
Estimates of international migration, by individual quarter, up to Quarter 2 (Apr to June) 2019. These quarterly estimates can be derived from the IPS but are not fully processed survey data and as such are not official statistics. For more information regarding this decision, see International migration -- terms, definitions and frequently asked questions (Section 10).

Interpreting individual quarter estimates

Estimates by quarter are not as robust as our estimates for rolling years and are not official statistics. This is because of the small sample sizes involved and because the complete methodology applied to our estimates for full years cannot be applied to our estimates for individual quarters. Users should be cautious with any interpretation of individual quarter estimates, especially where the corresponding confidence interval is large in comparison with the estimate.

Comparability of individual quarter data

Given the seasonal nature of international migration, where these data are used, we advise users to only compare the individual quarter data with the same quarter in the previous years. However, given the limitations with quality, methodology and coverage, we recommend using the estimates for rolling years over the individual quarter data.

Home Office Immigration Statistics, year ending September 2019
Release | Released 28 November 2019
Includes both short- and long-term visas (including dependants) for non-EEA nationals and is available for the year ending September 2019. The release includes more detailed statistics by visa category, citizenship and industry sector. The release also includes data on citizenship, asylum and resettlement, detention, and returns.

National Insurance number allocations to adult overseas nationals: January 2002 to September 2019
Release | Released 28 November 2019
Includes both short- and long-term migrants for the year ending September 2019. The summary tables provide more detail by nationality and location of registrations in the UK.

Differences between the data sources are described in August 2019 progress report.

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10. Glossary

Long-term international migrant

The Office for National Statistics's (ONS's) migration statistics use the UN-recommended definition of a long-term international migrant: "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."

EU citizenship groups

EU estimates exclude British citizens. The following EU citizenship groups are used:

  • EU15: citizens of countries that were EU members prior to 2004, for example, France, Germany and Spain

  • EU8: citizens of Central and Eastern European countries that joined the EU in 2004, for example, Poland

  • EU2: citizens of Bulgaria and Romania, which became EU members in 2007. Between 2007 and 2013, these countries were subject to transitional controls restricting their access to the UK labour market; these restrictions were lifted on 1 January 2014

Home Office visa data are for non-EEA citizens. Non-EEA refers to citizens of countries outside the EU and excludes Iceland, Liechtenstein, Norway and Switzerland.

Work-related migration

In the International Passenger Survey (IPS), "Work-related" migration includes those people who migrate with a "Definite job" to go to already and those who migrate "Looking for work".

Full details of the terms and definitions used by the ONS can be found in International migration -- terms, definitions and frequently asked questions.

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11. Migration data sources

The sources of data included in this release are not directly comparable. However, taken together, the different sources of data provide a better indication of trends than any single source alone. This approach is explained in the Report on international migration data sources: July 2018 and the coherence report, which set out our latest understanding of the quality of International Passenger Survey (IPS) migration estimates.

Office for National Statistics (ONS) long-term international migration estimates

The main data source for estimates of long-term international migration is the IPS, which captures migrant intentions. The ONS publishes two types of estimates for long-term international migration: the IPS and Long-Term International Migration (LTIM) estimates.

LTIM estimates are based on IPS data but with the following adjustments:

  • migrants not included in the IPS survey, such as asylum seekers and refugees, and migrants entering or leaving the UK across the un-surveyed land border with the Republic of Ireland

  • migrants changing their intentions with regard to length of stay

It is only possible to perform the LTIM adjustments described here for estimates by a single characteristic such as citizenship or reason for migration. Where estimates involve more than one characteristic, such as estimates by citizenship and reason for migration, estimates are published that are based solely on the IPS data.

The Migration statistics first time user guide describes these data and the Long-Term International Migration estimates methodology details the method used to calculate LTIM estimates.

For more detailed information on our migration statistics methodology, please see International migration methodology.

ONS labour market estimates

The ONS produces estimates of the labour market activity of the resident population in the UK by nationality and country of birth from the Labour Force Survey (LFS). Statistical significance testing is not available for the labour market EU and non-EU breakdowns.

A number of differences have been identified when making comparisons between migration data from the Annual Population Survey (APS), LFS and IPS. On 21 August 2019, we published a report outlining the findings from research into differences between these survey sources.

Home Office data

Home Office immigration statistics provide the numbers of people who are covered by the UK's immigration control and related processes, based on a range of administrative and other data sources. Where direct comparisons are made to the IPS data, Home Office visa data are for main applicants only and for long-term visas (one year or more). The Home Office immigration statistics: user guide provides more detail.

The Migration research and analysis page brings together a range of statistical and research reports on migration published by the Home Office.

Department for Work and Pensions (DWP) data

The DWP National Insurance number (NINo) statistics count the volume of NINos registered to adult non-UK nationals. Further information, including detail on data sources, uses and limitations of the series, is provided in the background information.

Population and migration statistics transformation

The Government Statistical Service's (GSS's) population and migration statistics transformation programme is working towards putting administrative data at the core of international migration statistics. The transformation overview report provides the latest update on the transformation journey.

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12. Strengths and limitations of the ONS international migration data

The International Passenger Survey (IPS) and the Long-Term International Migration (LTIM) estimates are currently the only sources of data to provide both long-term immigration and emigration and so net migration estimates for the UK.

The IPS is a sample survey and as such provides estimates. When the estimates are broken down beyond the headline figures, they are subject to greater levels of uncertainty.

To ensure confidence in our estimates, we review all available data sources to make the best assessment of migration in the UK. For example, Home Office administrative data on non-EU citizens travelling are more detailed and do not have the known possible variability present in estimates made from sample surveys.

The accuracy of long-term migration estimates

Surveys gather information from a sample of people from a population, as it is not possible to ask every person travelling in and out of the country to fill out a survey. This means we have to estimate total changes, which can be affected by the group of people we sample. We use confidence intervals to measure uncertainty around the estimate. Users are advised to be cautious when making inferences from estimates with relatively large confidence intervals.

Preliminary adjustments to LTIM estimates based on all available sources

To get the best overview of trends in migration, we need to look at all available data sources. To help us address the impact of uncertain intentions for non-EU students at the end of their studies and for EU8 citizens moving to the UK, we have applied preliminary adjustments to our IPS-based estimates based on administrative data from the Home Office and from the Department for Work and Pensions (DWP). These tell us about people’s actual behaviour and help provide a fuller assessment of migration patterns.

For EU migration, our preliminary adjustment applies up to March 2016, drawing on the strengths of what DWP data tell us about National Insurance number (NINo) registrations by people born in EU8 countries. From 2016, we have seen some changes to the trends in net migration for EU countries, and so we are reviewing what further data sources can add evidence on which to base an adjustment after this point.

For non-EU migration, our preliminary adjustment applies from 2012 through to the latest quarter. This draws on the strengths of what Home Office data tell us about emigration of non-EU students.

Fuller details on the methods we have used to apply adjustments to the data can be found in the research report.

Revisions to the ONS migration estimates

Revisions to net migration estimates in light of the 2011 Census were made in April 2014. The report, a summary and guidance (PDF, 56KB) on how to use these revised figures are available.

Owing to an unusual pattern in student migration seen between the year ending September 2016 and the year ending September 2017, revisions were made in February 2019 to LTIM and IPS estimates for non-EU formal study immigration. A guidance note has been published to explain the revision. The revision affects estimates for the years ending September 2016, December 2016, March 2017 and June 2017. As non-EU student immigration feeds into overall immigration and net migration estimates, we have also produced revised estimates for these figures.

Imbalance and discontinuity work

The IPS has recently transferred outputs from data collected on paper forms to an improved method using tablet computers. Tablet data collection was phased in gradually from September 2017 to April 2018. More background information about the rollout is available.

The new tablets enable us to improve the quality of the IPS data collected. However, discontinuities (that is, step changes in the time series) arising from the introduction of tablet data collection in the IPS are possible. We have worked with academic experts and the Office for National Statistics (ONS) Methodology Team to produce a method for detecting any such discontinuities.

We have continued to monitor the results as more data have become available. Further analysis using a longer series of data is required to determine whether there are any discontinuities, so some caution is still advised in the interpretation of data in this release.

Methodological changes are planned to the estimates of international visitors in the IPS. These are weighting adjustments to address concerns about the imbalance (that is, large differences in numbers) in the IPS between the estimates of numbers of visitors arriving and departing, for some nationalities. The new method has been developed in consultation with users and methodological experts. We plan to implement the new method to the overseas travel and tourism statistics next year. A revised back series will also be published at this time. More information about the planned changes will be published as soon as possible.

Please note that while the imbalance work is unlikely to affect long-term migrants in the IPS, we have committed to exploring whether the survey processes that cause the imbalance in international visitor estimates also impact on long-term migration further, as part of ONS Migration Statistics' workplan to understand different migration data sources.

The changes in data collection methods and planned methodological changes were described in the Travel trends 2017: recent data collection changes and planned methodological changes article, in July 2018.

Quality and methodology

The Long-Term International Migration Quality and Methodology Information (QMI) report contains important information on:

  • the strengths and limitations of the data and how it compares with related data

  • the uses and users of the data

  • how the output was created

  • the quality of the output including the accuracy of the data

For more detailed information on our migration statistics methodology, please see International migration methodology.

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Contact details for this Statistical bulletin

Ann Blake
migstatsunit@ons.gov.uk
Telephone: +44 (0)1329 444097