This case study sets out early experimental analysis of linked Higher Education Statistics Agency (HESA) and Home Office Exit Checks data, with the aim of understanding what linking HESA and Home Office Exit Checks data can tell us about departure patterns and length of stay of non-EU students at the local authority level. The findings from this case study provide important insights that will be key to the successful development of a population and migration statistics system based on administrative data sources.

1. Transforming population and migration statistics
Case Study: Emigration patterns of non-EU students
Centre for International Migration
Published: 30th January 2019
Coverage: England and Wales, academic year 2015/16 and 2016/17 and Exit Checks data covering August 2015 – December 2017
1
These Research Outputs refer to non-EU international students in HESA data
who have been linked to Home Office Exit Checks data, and are not Official
Statistics. These research outputs must not be interpreted as an indicator of
the numbers of international students departing from England and Wales, or
as a representative sample of all departing students.
Key messages
• This slide pack sets out early experimental analysis of linked Higher
Education Statistics Agency (HESA) and Home Office Exit Checks data.
• We linked around 80% of HESA records with a course end date
between August 2015 and July 2017, for non-EU students to Home
Office Exit Checks data.
• Most non-EU students departed long term at the end of their studies
(around 70%). 26% of each cohort extended their stay in the UK, or
departed short-term and returned on a long-term visa
• New analysis of linked HESA and Home Office Exit Checks data for
England and Wales indicates that 10% of graduating non-EU students
that emigrated long-term left within a week of their course end date
(either a week before or a week after).
What can linking HESA and Home Office Exit Checks data tell us about departure patterns and length of
stay of non-EU students at the local authority level?
Source: ONS analysis of linked HESA and Home Office Exit Checks data
Analysis of length of time between course end date and last
departure recorded in Exit Checks data, as a proportion of
students who emigrated long-term
0
5
10
15
20
25
-Morethan12
-12
-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1week-1month
-upto1week
+upto1week
+1week-1month
+2
+3
+4
+5
+6
+7
+8
+9
+10
+11
+12
+Morethan12
%
15/16
16/17

2. What are Tier 4 (sponsored study) visas, and how
many are granted each year?
Tier 4 (sponsored study) provides a route for students to study
with an approved education provider. Tier 4 of the points based
system (PBS), which provides a route for students to study with
an approved education provider, was implemented from 31
March 2009, replacing previous entry routes for study.
In year ending June 2018, 154,000 Tier 4 visas were granted for
long-term study.
Quarterly and annual statistics published by the Home
Office1 relating to those non-European Economic Area (EEA)
coming to the UK for study are available. These figures include
both long and short term immigrants.
1 https://www.gov.uk/government/statistics/immigration-
statistics-year-ending-june-2018
2
Background
This case study aims to build on our earlier research into international
student migration. We have used Home Office administrative data to
understand non-EU students’ departure patterns and length of stay at
the local authority level.
Data sources 1. Higher Education Statistics Agency (HESA) student records
2. Home Office Exit Checks data
Time period HESA academic years - 2015/16 and 2016/17
Exit Checks data for visas expiring between August 2015 and December 2017
Population of interest HESA: Two cohorts of non-EU students (identified by nationality) registered at Higher Education
Institutions (HEI) in England and Wales in 2015/16 and 2016/17.
Exit Checks: Two cohorts of non-EU nationals on Tier 4 student visas studying at England and Wales
HEIs and identified as usually resident whose visas where due to expire in 2015/16 and 2016/17
Methodology See slide 13
Things you need to know See slide 14
Other research into movement of international students
• The Migration Advisory Committee (MAC) have published a report on the impact of
international students in the UK, exploring how they impact the economy, educational
institutions, domestic students, and wider communities.
• ONS have published a research output investigating what international students do after
completing their studies.
• The 2017 CPC-ONS-UUK Survey of Graduating International Students (SoGIS) analysed
patterns of working for international students approaching course completion, mainly
focused on those studying postgraduate degrees. A follow up survey was undertaken in
2018.
• Department for Education (DfE) published time-series data showing international
graduate outcomes 2006-2016 based on their Longitudinal Education Outcomes dataset.
Links to all of this work can be found on slide 14

3. 3
HESA Student data Home Office Exit
Checks data
Unlinked HESA students
HESA records that could not be linked to Exit Checks using
1-1 matches. More detail about who these residuals are
presented on the next slide.
Linked data – HESA graduating non-EU students
linked to Exit Checks data.
We are still developing our data linkage methods but we wanted to
show early progress. This analysis is based on 1-1 matches, therefore
we will be missing potential links. Match rates are presented on the
next slide.
Background
Unlinked Exit Checks
records
Exit checks records that could
not be linked to HESA using
1-1 matches. More detail
about who these residuals are
presented on the next slide.
All those on a study visa
sponsored by an
institution in HESA
All non-EU students who
should require a visa to
study and therefore
should be on Exit
Checks

4. How we linked the data
HESA and Exit Checks data do not share a common unique identifier such as National Insurance number, NHS number or
passport number. The linkage between HESA and Exit Checks data was done using the ONS matchkeys methodology1 to produce
1-1 matches.
1 - http://www.ons.gov.uk/ons/about-ons/who-ons-are/programmes-and-projects/beyond-2011/reports-and-publications/beyond-2011-matching-anonymous-data--m9-.pdf
Our matching produced a high level of links. We linked 80% of records for non-EU students in HESA for 2015/16 and 74% of records for
2016/17. 20% and 26% of records for non-EU students were not linked to the Exit Checks data. This may be due to linkage error (i.e. should
have matched, but didn’t) or they were not captured in the Exit Checks data (for example, they may have departed before the Exit Checks
program started in April 2015, departed via the Common Travel Area, or for other reasons as reported in our analysis of international students
using Exit Checks data 2).
2 - https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/internationalmigration/articles/whatshappeningwithinternationalstudentmigration/2017-08-
24
Match rate 2015/16
(%)
2016/17
(%)
HESA records linked to
Exit Checks data
80 74
050000 Linked HESA and Exit Checks Unlinked HESA records
Analysis
Our analysis only includes non-EU nationals on Tier 4 study visas who are studying in England and Wales for 12 months or more (identified
on the Exit Checks data) who linked to the HESA data. These account for 62% of all matched records. The remaining 38% of matched records
excluded from our analysis tended to be similarly aged and more mature. We plan further exploratory research into this group.
0
10,000
20,000
30,000
40,000
50,000
Under 15 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65+
Count
Linked HESA and Exit Checks Males Unlinked HESA records Males Linked HESA and Exit Checks Females Unlinked HESA records Females
The chart below shows the age and sex distribution for linked HESA and Exit
Checks records and also unlinked HESA records for the 2016/17 cohort for our
population of interest.
These distributions look broadly similar, but a large number of non-EU students have
not linked to Exit Checks data and will be under-represented in our linked dataset.
Further work is being done to look at other characteristics, such as nationality

5. 5
13% of non-EU national
graduating students in 2016/17
HESA data are missing Term-
Time Local Authority (TTLA)
information (compared to 5% of
graduating UK national students).
These charts show that part-time
and dormant non-EU students are
more likely to be missing a TTLA
compared to other study modes.
Examination of missingness by
course stage suggests that for
those on multi year courses, final
year students are more likely to be
missing TTLA information than
students earlier in their studies
(i.e. those in first year or middle
years of multi year courses),
where a course stage is known.
Using HESA data on term-time local authority to understand where graduating non-EU students are leaving
from, England and Wales
The quality of key variables in the HESA data is crucial for
understanding where graduating non-EU students leave
from; so our findings must be seen in the context of levels of
missingness for TTLA.
These distributions are based on all HESA records for our
population of interest, whereas our linked data covers those
in their last year of study (contained in groups 1, 2, 5 and
potentially 9 in the above chart).
Our linked data have lower levels of missingness for TTLA
compared to all HESA records for non-EU graduating
students.
Number of records
missing TTLA
Proportion of
records missing
TTLA
15/16 16/17 15/16 16/17
HESA only 21,000 23,000 12% 13%
Linked HESA-Exit
Checks
5,000 5,000 5% 6%
TTLA = Term time Local Authority, the area HESA records the student as living.
Dormant = Students who have suspended study, but have not formally deregistered.
0
5
10
15
20
25
30
35
40
45
%
Percentage of non-EU
students missing term time
LA by study mode (16/17)
0
10
20
30
40
50
60
70
80
90
1 - Course
academic
year
contained
within the
HESA
reporting
period 1
August - 31
July
2 - Course
academic
year not
contained
within the
HESA
reporting
period 1
August - 31
July
3 - Student
commencing
a course
running
across
HESA
reporting
years.
4 - Student
mid way
through a
course
running
across
HESA
reporting
years.
5 - Student
finishing a
course
running
across
HESA
reporting
years.
9 - Not
known.
%
Percentage of non-EU students missing term
time LA by course stage (16/17)
Source: ONS analysis of HESA data,
England & Wales Source: ONS analysis of HESA data, England & Wales

6. Outcomes for two cohorts of graduating non-EU students in the linked HESA and Exit
Checks data show that the majority departed long-term
Our linked data shows that the majority of students in
the two cohorts (71% and 70% respectively)
departed long-term.
A further 26% in each cohort respectively extended
their stay in the UK, or departed short-term and
returned on a new long-term visa.
This supports previous analysis reported in August
2017 and July 2018.
Source: ONS analysis of linked HESA and Home Office Exit Checks data
Status of two cohorts of graduating non-EU students in the linked HESA and
Exit Checks data, England and Wales
This analysis is based on two cohorts of graduating non-EU students in the linked HESA and Exit Checks data.
We linked a further 12 months of travel event data to examine, for these cohorts, who returned within 12 months of their last
departure.
From this we are able to identify those who departed long-term (did not return within 12 months or are assumed not to have
returned as the evidence of a return is inconclusive), those who returned within 12 months and stayed long-term or on a short-
term visit visa and those with no initially identified departure, or evidence of departure is inconclusive.
No initially identified departure in the Exit Checks data, may be due to non-matching of individuals, departure via the Common
Travel Area or other reasons, as well as those who left before April 2015. Further details of the possible reasons for non matching
were detailed in the Home Office’s report on Exit Checks data.
0
10
20
30
40
50
60
70
80
Departed long-term Extended leave to remain
or returned on new long-
term visa
Departure not initially
identified or departure date
is missing in Exit Checks
%
15/16 16/17

7. The majority of graduating non-EU students in our two cohorts departed England and
Wales within 4 months of the course end date reported in the HESA data
Our linked data allows us to look
at whether non-EU students
leave before or after their course
end date reported in HESA data.
Tier 4 student visas allow up to
4 months leave after course end
date (dependant on course
length), which enables students
to attend graduation or look for
work, and therefore will not
exactly match HESA course
start and end dates.
10% leave within a week of their
course end date.
A further 24% leave between 1
week and 1 month of their
course end date.
This analysis is based on those
who were identified as having
departed in the Exit Checks data
and excludes those who
extended their leave to remain
for study or other reasons
Source: ONS analysis of linked HESA and Home Office Exit Checks data
Analysis of length of time between course end date and last departure
recorded in Exit Checks data , as a proportion of students that emigrated
long-term
In the above chart, a negative time period indicates that the last recorded departure date was before a course
end date. A positive time period indicates that the last recorded departure date was after a course end date.
This analysis is based on non-EU students who departed long-term (12 months or more) in the linked dataset.
Long-term departures are identified in Exit Checks data as those students who didn’t return within 12 months of
their last departure date or returned within 12 months of their last departure date for a short period lasting less
than 12 months.
This analysis is not representative of all non-EU students who departed long-term as some may have had a
visa expiry date before our period interest or after our period of interest. In addition, instances of students
departing more than 4 months after their course end date may be due to the incorrect leave instance in the Exit
Checks data being assigned to a HESA study instance. We have plans to investigate this further.
0
5
10
15
20
25
%
15/16
16/17

8. Using linked HESA and Home Office administrative data to understand graduating
non-EU student departure patterns for local authority areas
The aim of this exploratory research is to explore the departure patterns for graduating non-EU students at a local authority level. We are only able to do this
for the linked dataset, which is not fully representative of all graduating non-EU students at a local authority level.
There is more work for us to do to understand the residuals in the HESA and Exit Check data linkage for our population of interest, and whether it is possible
to identify if they departed (HESA residuals) and where they departed from (Exit Checks residuals/HESA data with no term-time local authority data). This
analysis and further improvements to our initial linkage will inform our future work to look at the feasibility of producing emigration and immigration estimates
for non-EU international students at subnational and local levels.
We have shown here, for illustrative purposes only, what may be possible once this further work has been done. In this example we show, for a university’s
local authority, likely departure patterns for graduating non-EU students, based on our linked dataset.
Status of two cohorts of graduating non-EU students in
the linked HESA and Exit Checks data, Local Authority A
Source: ONS analysis of linked HESA and Home Office Exit Checks
data
Source: ONS analysis of linked HESA and Home Office Exit Checks data
Analysis of length of time between course end date and last departure
recorded in Exit Checks data, as a proportion of students who
emigrated long-term, Local Authority A
0
10
20
30
40
50
60
70
80
Departed long-term Extended leave to
remain or returned on
new long-term visa
Departure not initially
identified or departure
date is missing in Exit
Checks
%
15/16 16/17
0
5
10
15
20
25
30
35
-12ormore
-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-8-30days
-7days
+7days
+8-30days
+2
+3
+4
+5
+6
+7
+8
+9
+10
+11
+12
+12ormore
%
15/16 16/17

9. Using linked HESA and Home Office Exit Checks data has also allowed us to examine how
much time non-EU students spend in England and Wales over a 16 month period
• Our linked data allows us to test the
assumption that appearing on HESA data is
evidence that an international migrant is
actually residing in England and Wales.
• Our analysis has shown that a large
proportion (47%) of students spend
between 300-400 days in the England and
Wales during their first 14 months of study
within a 16 month period.**
• The median (shown as the purple bar in the
chart) lies at 331-340 days, which is less
than a year.
• This analysis is useful for informing the
work we are undertaking to look at the
different conceptual definitions for
international migration (long-term, short-
term or circular patterns of movement).
0
2000
4000
6000
8000
10000
12000
14000
16000
0-10
21-30
41-50
61-70
81-90
101-110
121-130
141-150
161-170
181-190
201-210
221-230
241-250
261-270
281-290
301-310
321-330
341-350
361-370
381-390
401-410
421-430
441-450
461-470
481-490
Number of
linked students
Number of days in UK within 16 month period of interest
Source: ONS analysis of linked HESA and Home Office Exit Checks data
** This analysis is based on the linked
dataset only and will not be representative of
all non-EU first year students.
We chose to look at length of stay over a 16
month period to validate other analysis we
are doing to produce estimates of non-EU
long-term immigration using a rule that a
migrant must be present for 12 out of 16
months to be a long-term migrant.
Time spent in England and Wales, non-EU first year students studying
at Higher Education Institutions in England and Wales

10. Putting administrative data at the core of our evidence on international migration (UK) and on
population (England and Wales) by 2020
The findings from this case study provide important insights that
will be key to the successful development of a population and
migration statistics system based on administrative data
sources.
Future analysis of the patterns of international migrants’
interactions with these datasets will also inform statistics on
other migration-related topics such as the impact of international
students.
Next steps
To continue our research into travel
patterns and length stay for non-EU study
migration, using Exit Checks data in
collaboration with Home Office experts.
It provides evidence for:
• Development of a Statistical Population Dataset from linked
administrative data
Linking HESA data to Exit Checks data can confirm usual
residence status and also identify potential over- or under-
coverage in these data sources. So far, our linkage has shown
that some female non-EU students may be under-represented
in our current extract of Home Office Exit Checks data.
• Development of rules for stocks and flows approaches
Exit Checks are a key data source for a flows based population
model. Using these data together, we are be able to identify
when non-EU students arrived and departed and understand
the complexity of travel patterns.
‘Signs of activity’ analysis show total number of days stayed by
international students. This will inform thinking around concepts,
rules and definitions to identify this group in stocks or flows.

11. Covered Gaps
Geographical Coverage • Government funded Higher Education
Institutions (HEIs) in England and Wales
• Other Government funded HEIs in
the UK
Patterns of movement • Departures at local authority or regional level
for linked dataset where term-time postcode is
known
• Time spent in the UK for non-EU students on
Tier 4 study visas (first year students)
• Departures at local authority or
regional level for residuals
• Immigration at local authority or
regional level
• Time spent in UK for non-EU
students on Tier 4 study visas
(other years). Further analysis by
course type, study location and
course length.
• Extend to EU nationals when data
become available
Population of interest • Non-EU students (identified by nationality)
registered at Government funded HEIs. Non-
EU nationals on Tier 4 student visas studying
at England and Wales HEIs and identified as
usually resident.
• Extend to EU nationals when data
become available
Completing the picture

12. • Continue our collaboration with Home Office experts to better
understand Home Office administrative data.
• Build on existing linkage to produce a linked dataset that can be used
for statistical purposes. This will involve further improvements to our
linkage process and understanding of residuals.
• Building on the above, explore the feasibility of producing estimates of
student emigration and immigration at a sub-national, regional and local
authority level.
• Once acquired by ONS, link HMRC PAYE Real Time Information (RTI)
to Exit Checks data for more granular analysis of non-EU migrants on
non-study visas (e.g. skilled work) and their patterns of movement and
impact on economy.
• Also explore linking RTI data to HESA-Exit Checks cohort data for
further granular analysis looking at movements of students who extend
into skilled work routes.
• Develop methods to identify, classify and analyse different types of
international migrants using these linked data sources.
Next steps

13. 13
Things you need to know
The Home Office Exit Checks programme, introduced in April 2015, was designed primarily for operational (immigration control)
purposes, and collected data on non-EU nationals departing from and arriving in the UK. The Initial Status Analysis system, developed
by the Exit Checks programme, is a linked database that combines data from Home Office systems to build travel histories that consist of
an individual's travel in or out of the country, together with data relating to immigration status e.g. periods of leave granted. This
combined data is used by the Home Office for operational and security purposes in the assessment of an individual’s immigration status.
Statistics are derived by integrating and matching data from multiple administrative systems, including (via carriers) passenger data,
passport scans at the border, and from immigration records. Producing statistics from these multiple sources presents a range of
challenges. Nevertheless, it has been possible to produce useful statistical insights and practical operational benefits for the Home Office
and to help ONS better understand non-EU migration patterns.
To analyse Exit Checks data, it is necessary to bring together, match and assess multiple individual events from different data systems to
produce an ‘identity’. The resultant dataset is termed the ‘Initial Status Analysis’. An example of these relationships is shown below.

14. Things you need to know
• Disclaimer: These Research Outputs on non-EU international student departure patterns and length of stay are not
Official Statistics.
• Rather, they are published as outputs from exploratory research to show users of international migration statistics where we
are on our transformation journey to put administrative data at the core of our evidence on international migration (UK) and on
population (England and Wales) in 2020.
• These research outputs must not be interpreted as an indicator of the numbers of international students departing
from England and Wales, or as a representative sample of all departing students.
• These research outputs are based on experimental analysis of linked HESA and Home Office Exit Checks data. We are still
developing methods, therefore the numbers or proportions reported here may change in future reporting on our journey to put
administrative data at the core of our evidence on international migration (UK) and on population (England and Wales) by
2020.
• It is important that the information and research presented here be read alongside the population and migration statistics
transformation update report to aid interpretation and avoid misunderstanding.
• These research outputs must not be reproduced without this disclaimer and warning note.
Other research into movement of international students
• The Migration Advisory Committee (MAC) have published a report on the impact of international students in the UK, exploring
how they impact the economy, educational institutions, domestic students, and wider communities.
• ONS have published a research output investigating what international students do after completing their studies.
• The 2017 CPC-ONS-UUK Survey of Graduating International Students (SoGIS) analysed patterns of working for international
students approaching course completion, mainly focused on those studying postgraduate degrees. A follow up survey was
undertaken in 2018.
• Department for Education (DfE) published time-series data showing international graduate outcomes 2006-2016 based on their
Longitudinal Education Outcomes dataset.

15. Contact Us
We would welcome your feedback on the exploratory research
presented here. Please get in touch at:
Email: pop.info@ons.gov.uk
Tel: 01329 444661

16. Further Links
Go back to: An update on our population and migration statistics transformation journey: A research
engagement report
Explore our other case studies on SlideShare
Transforming population and migration statistics: Administrative data-based population stocks and
flows
Transforming population and migration statistics: International student employment activity
Transforming population and migration statistics: Benefits and income activity patterns
Transforming population and migration statistics: NINo and NHS registration lags
Transforming population and migration statistics: Patterns of circular movement into the UK