Official Statistics

Developments in Exit Checks

Published 24 February 2022

The Reports on Statistics Relating to Exit Checks have historically provided updated results on the proportion of non-EEA nationals recorded as having departed before the expiry of their visa, or their temporary leave to enter or remain, as well as updated data quality metrics for Exit Check data collected by the Initial Status Analysis (ISA) system.

The ISA system combines data from different administrative sources to link individuals’ travel in or out of the UK with their immigration history.

The ISA system was designed primarily for operational purposes rather than to produce statistics. The results are based on matching data from multiple administrative datasets. This is a relatively new approach with significant technical challenges, and the figures are therefore experimental estimates (and have been designated as ‘experimental’ national statistics).

Individuals with no departure recorded are not necessarily still present in the UK. Their departure may not have been recorded, or data on their departure may have been recorded but not have matched against their arrival by the system.

1. Challenges and Changes in Measuring Migration

1.1 COVID-19

The UK visa system has been impacted by COVID-19 due to travel restrictions, lockdowns and changes in people’s travel patterns or intentions to travel. These effects have been discussed in our Immigration statistics.

As a result of these changes, we need to examine and fully understand the impact of COVID-19 on both the ISA system and Exit Checks data, to determine how this data has been affected by the pandemic. The challenge is further compounded by the impact of COVID-19 visa extensions. Extensions to leave have historically been excluded from our analysis, but the large number granted during the pandemic means that extensions now need to be integrated in our data in order to draw meaningful conclusions. This work is complex and ongoing.

1.2 Further Leave

The term ‘Further Leave’ is used here to encompass those whose visas ended, who were granted additional leave to remain in the UK at the end of their visa (including COVID-19 visa extensions).

Further leave allows us to identify outcomes for all those holding a visa, who are then granted further leave to remain within the UK. At the point of their previous leave expiring, the following criteria need to be met:

• the person must be in-country
• the person needs to have had another grant of leave either overlapping or immediately following the first.

Examples of people with Further Leave are those who:

• changed visa (for example moving from a study visa to a work visa, or from a work visa to a different work visa)
• get a new visa on the same visa route (for example going from a work visa to another work visa)
• gained indefinite leave to remain

The vast majority of these cases will be “extensions” (see the Home Office immigration statistics: user guide For further information on extensions), but there are exceptions. For example:

• if a person is out of the country when their previous leave expires, they will be given a “compliant departure” status, regardless of whether or not they held Further Leave. They may therefore have an extension but will not be classed as having Further Leave.

• if a person has overlapping entry clearance visas, they will receive a Further Leave status if they are in country at the point of expiry. They will not be classed as having an extension.

We have been investigating the presence of Further Leave data within ISA, developing our understanding of this data, and exploring the feasibility of adding information to the published statistics. The inclusion of this data will provide new opportunities to better understand the picture of visa outcomes and will provide new insights. More developmental work is needed before we will be able to understand this data.

Further leave data will be necessary to understand the impacts of COVID-19 leave on Exit Checks. Granting COVID-19 related extensions caused non-EEA visa nationals to move from our visa expiry data into the Further Leave category. The number of people within this year’s Further Leave results will, therefore, be higher than normal. Similarly, the number of visas expiring with no matched departure will be lower than normal. These COVID-19 related extensions are due to expire within the year ending March 2022. Some of these people may already have left the country or may not have been present when granted this Further Leave, adding further uncertainty to the underlying ISA data, further emphasising the need for us to accurately understand what has happened.

1.3 EEA data and ISA

The UK’s Immigration system is undergoing a period of unprecedented change, both through the introduction of a new points-based system and new immigration routes (especially for EU nationals) and the development of a number of new back-office systems which will replace previous systems from which the data on visas and border crossings were drawn.

In the year following the Fifth report on statistics relating to exit checks, data relating to EEA nationals’ travel movements started being ingested into ISA. This data had not previously been available to ISA. This ingestion has allowed for better data linking of records relating to people who have used a mixture of EEA and non-EEA travel documents (e.g. dual nationals). This in turn allows for more departures to be matched to visa expires and potentially, a better understanding of visas with no matched departure in ISA.

It is difficult to separate the effects of ingesting EEA data on visa ‘identified in-time departures’ from the improvements normally seen in data linking due to ingestion of other new data. However, as an example, the rate of visas with no matched departure in ISA for non-EEA nationals arriving on EEA family permits in the year ending March 2019 was 35% prior to the ingest of this EEA data and 24% after the addition of this EEA data.

The inclusion of EEA data is ongoing, and new EEA data will allow for further matches between departures and visa expiries. EEA nationals’ travel movements will include people who are normally resident in the UK (for example, those with status under the EU Settlement Scheme) as well as people who have obtained a visa under the new Immigration system.

1.4 EUSS data and ISA

Following the opening of the EU Settlement Scheme (EUSS) on 29 March 2019, the Home Office has published summary statistics on the scheme, with headline figures updated monthly on the main EUSS statistics landing page and more detailed breakdowns provided in a quarterly report. EUSS data is being ingested into ISA, and we expect the inclusion of EUSS data will provide further opportunities for better data linking of records, as has occurred for the EEA data, and new insights into this cohort.

1.5 Mixed Identity improvements within ISA

The ISA system is a person-centric database of linked travel and travel-related data which is known to have made some false positive matches. In this case, false positives will manifest themselves as identities containing events relating to two or more real individuals that have been incorrectly linked together to form one identity.

In 2020, a new mixed identity flag was developed. To validate the new flag, a sample of ISA identities that had been identified as mixed or not mixed by the new logic were clerically reviewed. The clerical review classified each identity as either mixed or not mixed to provide a ‘gold standard’ to compare the new method against. The new flag was also compared against the old flag as a further validation step, and to understand how the performance of the two methods differed. The new flag significantly improved specificity and sensitivity, and has therefore been implemented.

The use of the new flag caused very little change in the percentage identified in-time departure (between 0.0% and 0.2% for all visa types recorded) using ISA data from the year ending March 2020.

1.6 Quality Metrics for Exit Checks Data

Border Force ceased reporting Coverage and Aviation data receipt, from June 2020. The last set of Coverage and Aviation data receipt published statistics can be found in the ‘Fifth report on statistics relating to exit checks’.

• Coverage was a measure of the degree to which those routes that are in scope have systems in place that allow submission of data to relevant Home Office administrative systems and hence to ISA.

• Aviation data receipt (formerly Completeness) was the percentage of voyages where at least one Passenger Check-in and one Departure Confirmation message was received. This measurement does not mean that data for every passenger on a voyage was received.

In their place, Border Force have introduced new Data Receipt and Data Quality metrics.

• Data Receipt – Figures relate to the percentage of voyages where at least one Passenger or crew Check-in or Departure Confirmation message was received. This measurement does not mean that data for every passenger or crew member on a voyage was received. Please note that this is not directly comparable to the metric of Aviation data receipt, which was used in previous publications.

• Data Quality – is composed of:

  • Timeliness
  • Field level data quality
  • Missing ‘Check In’ data where a ‘Departure Confirmation’ has been received (which confirms someone actually travelled and is used to create a travel history).

All carriers on a specified route are required to provide data for their flights, voyages or rail journeys. Some routes are still implementing their systems to be able to provide this information.

1.7 Accessibility

In August 2020 we updated the annual experimental statistics on Exit checks data (covering visa-compliance by visa route (e.g. study)), streamlining the presentation. We reduced superfluous text and clarified definitions to provide a more coherent, succinct narrative of the statistics. Furthermore, we reviewed and updated our statistical tables, in line with 2018 accessibility legislation, helping to ensure that they meet user needs.

2. Current Work with ONS

The Home Office is committed to supporting ONS’s (Office for National Statistics) cross-government programme of work on developing migration estimates and to continue to work together, along with our partners from the Government Statistical Service in other departments, to ensure that the statistical information on migration in the public domain is as coherent as possible and helps to inform policy development and public debate.

ONS’ analysis of Home Office border crossing and Exit Checks data continues to be a key aspect of their migration statistics development programme. We have been working with ONS, sharing information on the changes present within ISA due to the inclusion of data from new sources, such as EEA data.

We are working to support ONS’ creation of admin-based migration estimates (ABMEs), which use statistical models to bring data together and predict the likely outcome of long-term international migrants who have recently immigrated or emigrated. The aim is that ONS’ future system will link different sources of admin data to ensure wider population coverage and provide granular detail and insight into migration and the wider population. Home Office ISA is a key source of this information.

In November 2021, ONS published the first results of their work using ISA data to improve our understanding of international students and transitions within the UK.

3. Future plans

3.1 IT Systems Development Work

As noted earlier, the UK’s immigration system is undergoing a period of unprecedented change including the replacement, re-engineering and re-platforming of management information, statistical and data service systems. All of these changes have affected, and continue to affect, the way in which the department is able to use data in the short-term but of course will bring significant long-term benefits. As this work has developed, we have implemented strategies to ensure that our core functions, including the provision of statistics, are maintained.

3.2 Re-imagining the Migrant Journey and Exit Checks reports

We are currently investigating the effects of COVID-19 leave and the inclusion of EEA data in ISA. As part of this work, we are analysing Further Leave, which we believe will help to illuminate the changes to people’s travel patterns during this time of rapid change. Once EUSS data becomes available within ISA, we will study its impacts on the data, and what further value it can add to the bigger picture of migration.

These changes, largely the result of the COVID-19 pandemic, have meant that we have been unable to produce an Exit Checks report for the Year Ending March 2021.

We have decided to take this opportunity to review our two key ISA publications, the Migrant Journey and Exit Checks, to our customers.