Data sets on irregular migration and irregular migrants in the European Union

Abstract

This paper describes the main data sets that can be used to quantify trends of irregular migration and indirectly also the stock of irregular migrants in the EU. The review covers only data sets that are openly available and have supranational relevance.

Full text

Vol. VII, Number 2, April–September 2017
MIGRATION POLICY PRACTICE
26
Data sets on irregular migration and
irregular migrants in the European Union
Michele Vespe, Fabrizio Natale and Luca Pappalardo1
The evidence produced during the recent
migraon crisis in Europe is oen based on
data sets that have intrinsic limitaons of
coverage and availability, and that capture the
complex phenomenon of migraon from dierent
perspecves. Simple quesons such as “What is the
number of migrants in the European Union (EU)?”
cannot be answered by providing one single number
but a set of numbers where each number tells a
dierent part of the story.
Besides trying to expand the availability of data
on migraon, it is important to be aware of the
characteriscs of the exisng data sets since
knowledge of this determines the type of analysis and
conclusion that can be drawn from the data.
This paper describes the main data sets that can be
used to quanfy trends of irregular migraon and
indirectly also the stock of irregular migrants in the
EU. The review covers only data sets that are openly
available and have supranaonal relevance.
The measurement of irregular migrants is, by
denion, problemac since we are dealing with a
phenomenon that is outside the control of States.
Past iniaves like the European project Clandesno
and recent eorts by the European Migraon Network
point towards the possibilies to esmate rather
than measuring the number of irregular migrants.
Esmates produced by the project Clandesno refer
to gures for irregulars in Europe between 1.9 million
and 3.8 million in 2009.2
In addion to the intrinsic diculty of measuring
“irregularity”, confusion in public debates arises
oen from the assimilaon between the concepts of
“irregular migrants” and of “irregular migraon”. The
following denions help to clarify the fundamental
dierence between these two concepts.
1 Michele Vespe and Fabrizio Natale are Scienc Project
Ocers at the European Commission, Joint Research Centre
(JRC). Luca Pappalardo is Policy Ocer at the European
Commission, Directorate General for Migraon and Home
Aairs.
2 Clandesno Project Final Report (2009).
The Migraon Observatory at the University of Oxford
denes irregular migraon as “a ow of people
who enter the country without the country’s legal
permission. In contrast, the term ‘irregular migrants’
typically refers to the stock of migrants in a country
who are not entled to reside there”.3
Similarly, the European Migraon Network denes an
irregular migrant as “a person who, owing to irregular
entry, breach of a condion of entry or the expiry of
their legal basis for entering and residing, lacks legal
status in a transit or host country. In the EU context,
a third-country naonal present on the territory of a
Schengen State who does not full, or no longer fulls,
the condions of entry as set out in the Schengen
Borders Code, or other condions for entry, stay or
residence in that Member State”.4
From these denions, it emerges that the term
“irregular migraon” refers to the process of migraon
and to a ow of people, while the term “irregular
migrants” refers to the status of people and therefore
to a stock.
The idea of irregularity should not be interpreted as an
immutable characterisc of persons but is a label that
depends on conngent administrave and legislave
frameworks of the receiving countries, how these are
implemented, and how the results are captured by
operaonal, administrave and stascal reporng
systems.
The two concepts of irregular migrants and irregular
migraon are not necessarily linked and the
denion of irregular status may change over me.
For example, migrants entering legally into the EU
through a visa may acquire an irregular status if they
overstay the me limit of their visa, visa-free access
or residence permit. On the other hand, it is possible
to enter irregularly in Europe and be counted within
3 B. Vollmer, “Irregular migraon in the UK: Denions,
pathways and scale”, The Migraon Observatory Brieng
(2011).
4 European Migraon Network, Asylum and Migraon Glossary
3.0 (Brussels, 2014). Available from hps://ec.europa.eu/
home-affairs/what-we-do/networks/european_migration_
network/glossary/i_en (accessed 27 July 2017).

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the irregular border crossings, but, when applying for
asylum, be counted in the stock of persons staying
legally in the EU.
Changes in the total number of irregular migrants
may derive both from changes in irregular arrivals
and changes in the status of persons residing legally.
These changes in status can take place more than
once in one year, and several mes for longer me
periods. In addion, the stock of irregular migrants is
subject to the normal demographic changes of birth
or death and migraon which are applicable to the
general populaon.5 Finally, changes in status from
irregular to regular may be triggered by the detecon
itself. For example, it is oen the case that asylum
applicaons are lodged aer people are found to be
illegally present in the territory of EU Member States.
In Europe, there are no ocial stascs that are
directly measuring irregular migrants or irregular
migraon. Nevertheless, there are indirect and
direct methodologies and proxies that can be used
to esmate such quanes relying on surveys,
regularizaon processes and administrave data.6 An
example of indirect approaches to esmate the stock
of irregular migrants is the residual method whereby
the esmate is derived from the dierence between
the stock of all the legal residents in the country
at a given point in me and the net ow of regular
migraon. This method has been used in the United
States,7 but can hardly be applied in Europe since
census in Europe is believed to underreport irregular
migrants.8 An example of direct esmaon of irregular
migrant stocks is based on a scaling factor (mulplier
method) applied to known gures such as the rao
between regular and irregular stocks as extrapolated
from known sampled groups of the total populaon.9
This method can be valid at the naonal or regional
level but can hardly be extended at the EU level.
5 D. Vogel, V. Kovacheva and H. Presco, “How many irregular
migrants are living in the European Union: Counng the
uncountable, comparing the incomparable” (2009).
6 M. Jandl, “Methods for esmang stocks and ows of irregular
migrants”, in: Report on Methodological Issues, deliverable
D3 prepared for Work Package 2 of the research project
Clandesno (2008).
7 J.S. Passel, “The size and characteriscs of the unauthorized
migrant populaon in the U.S.” (Pew Hispanic Center, 7 March
2006).
8 M. Jandl, “The esmaon of illegal migraon in Europe”,
Migraon Studies, March 2004:141–156.
9 Clandesno Project Final Report (2009).
Another aspect that hinders the producon of accurate
esmates of the total number of irregular migrants in
Europe is the fact that in most cases the data cannot
be aggregated across dierent EU Member States,
since the same person may be counted more than
once in dierent naonal data sets. This is the case
for rst-me asylum applicaons, rst-me residence
permit applicaons or irregular border crossing data.
First-me10 asylum applicaons are indeed related
to single countries and there might be mulple
applicaons in dierent countries, though this seems
to be happening in a relavely low number of cases.
First-me residence permits can be granted twice to
the same person if the me between two consecuve
permits issued is more than six months. The issue
of double-counng is parcularly problemac in
the case of ow data of irregular migrants. Irregular
border crossings are, by denion, events that do
not correspond to the number of individuals since
the same person can cross borders irregularly several
mes, for instance, dierent EU external borders.
The issues of denions and double-counng briey
described above give an idea of the challenges that
hinder the measurement in absolute terms of the
number of irregular migrants in the EU.
Despite these challenges, the combinaon of gures on
the ows of irregular arrivals with stascs on asylum,
on regular visas and on the number of persons found
to be irregularly present (apprehensions) may give an
indirect indicaon at least of the underlying trends
that aect the size of the stock of irregular migrants.
The following table lists the main data sets that can
be used for such a purpose, and the next paragraphs
provide some examples of gures extracted from
these data, which can be used to elucidate their main
characteriscs and limitaons.
10 The term “rst me” implies no me limits and therefore a
person can be recorded as a rst-me applicant only if he/she
has never applied for internaonal protecon in the reporng
country in the past, irrespecve of the fact that he/she is found
to have applied in another Member State of the European
Union (EU). For more informaon, see hp://ec.europa.eu/
eurostat/cache/metadata/en/migr_asyapp_esms.htm

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Table 1: Data sets on irregular border crossings, mixed ows arrivals to the European Union and enforcement
of immigraon legislaon*
Data source Descripon Frequency Coverage
FrontexaDetecons of irregular border crossings Monthly EU land and sea external
borders
Internaonal
Organizaon for
Migraon (IOM)b
Mixed migraon ows in the Mediterranean and
beyond
Monthly EU land and sea routes
UNHCRcUNHCR refugees operaonal data portal Monthly Mediterranean situaon
Eurostat – asylum
applicaons
Asylum and rst-me asylum applicaons, by
cizenship, age and sex, including unaccompanied
minors (migr_asyapp)
Monthly EU–European Free Trade
Associaon (EFTA)
Eurostat – asylum
decisions
Decisions by cizenship, age, sex and type of status
(migr_asydec)
Yearly EU–EFTA
Eurostat – recognion
rate stascsd
First-instance decisions by outcome and recognion
rates
Quarterly EU–EFTA
Eurostat – enforcement
of immigraon
legislaon
Third-country naonals refused entry at the external
borders (migr_eirfs), found to be illegally present
(migr_eipre) and ordered to leave (migr_eiord)
Yearly EU–EFTA
* The European Asylum Support Oce (EASO) has a data collecon system gathering informaon on all key stages of the Common
European Asylum System; however, it does not disseminate raw data publicly. Key indicators are released in monthly reports (see www.
easo.europa.eu/informaon-analysis/analysis-and-stascs/latest-asylum-trends).
Notes: a See hp://frontex.europa.eu/trends-and-routes/migratory-routes-map/
b See hp://migraon.iom.int/europe/
c See hps://data2.unhcr.org/en/situaons
d See hp://ec.europa.eu/eurostat/stascs-explained/index.php/Asylum_quarterly_report
Daily data on arrivals are also available in naonal
data sources such as the Italian stasc dashboard
on arrivals from the Italian Ministry of Interior11
and the Summary Statement of Refugee Flows to
Eastern Aegean Islands from the Hellenic Ministry of
Digital Policy Telecommunicaons and Informaon.12
However, the usefulness of these naonal data
sources to produce an esmate for the enre EU is
conngent on the migraon routes and how they
evolve over me.
Irregular border crossings and arrivals of migrants
and refugees
The main data set to measure irregular migraon in the
EU is produced by Frontex and refers to the number
11 See www.libertaciviliimmigrazione.dlci.interno.gov.it/it/
documentazione/statistica/cruscotto-statistico-giornaliero
12 See http://mindigital.gr/index.php/component/
search/?searchwo rd=refugee%20flows&ordering=ne west
&searchphrase=all&limit=0
of irregular crossings on the EU borders. Similar data
on arrivals to the EU are also collected by IOM and the
Oce of the United Naons High Commissioner for
Refugees (UNHCR).
Frontex data disnguish the ow by route of entry and
provide indicaon of the geographical composion of
the ow in terms of naonality of origin but not in
terms of country of desnaon.
The informaon on origin and desnaon can be
obtained from the data on asylum seekers from
UNHCR and EUROSTAT. However, these data sets do
not necessarily represent an irregular ow but rather
a legimate status.
Since Frontex data are about events, they should
not be added across countries or routes as the same
person may cross the EU external borders several
mes and be counted more than once. Parcular care
must be taken especially when dealing with both land
and sea arrival data.

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In Figure 1, the data show dierent waves of EU
irregular border crossings through dierent sea
routes, from 2011 to the more recent seasonal trends
along the Central Mediterranean route. A spike in the
trend of arrivals can be observed along the Eastern
Mediterranean route, mostly due to Syrians eeing
the civil war in 2015 and 2016.
The seasonality paerns and spikes that are evident
from the me series of arrivals cannot be taken as
direct measure of the stock of irregular migrants but,
rather, they give an indirect indicaon of trends that
are aecng this stock.
Figure 1: Irregular border crossing by sea following the Central, Western and Eastern Mediterranean routes
0
50,000
100,000
150,000
200,000
2010-12 2011-06 2011-12 2012-06 2012-12 2013-06 2013-12 2014-06 2014-12 2015-06 20 15-12 2016-06 2016-12
Central Mediterranean route
Eastern Mediterranean route
Western Mediterranean route
Source: Frontex irregular border crossing data. Chart produced by the Knowledge Centre on Migraon and Demography (KCMD).
Short-stay Schengen visas
Stascs on short-stay Schengen visas,13 as shown
in Figure 2, represent regular rather than irregular
ows. Nevertheless, such stascs can give an upper
bound – signicantly approximated – of third-country
naonals that may overstay their Schengen visas.
There are three main caveats to be considered when
using such an approach. First, EU Member States and
Schengen countries do not fully overlap. Secondly,
the data refer to visas issued in consulates located
in non-Schengen countries and do not necessarily
represent the naonalies of the people making the
request. Finally, the share of people overstaying their
visas is not known and it is expected to depend on the
13 See hps://ec.europa.eu/home-aairs/what-we-do/policies/
borders-and-visas/visa-policy#stats
naonality (some third-country naonals are more
likely to overstay than others).
It is worth menoning that the planned Entry/Exit
System (EES)14 will eventually register third-country
naonals crossing the Schengen external borders
and systemacally oer the possibility to idenfy
overstayers.
14 European Commission, “Proposal for Regulaon of the
European Parliament and of the Council establishing an
Entry/Exit System (EES) to register entry and exit data and
refusal of entry data of third country naonals crossing the
external borders of the Member States of the European Union
and determining the condions for access to the EES for law
enforcement purposes and amending Regulaon (EC) No
767/2008 and Regulaon (EU) No 1077/2011”, COM (2016)
194 nal.

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Despite these limitaons, Figure 4 shows that the
macro trends of asylum applicaons in 2015 are
reected in a lagged trend for the following stages
of rst-instance decisions. The number of negave
decisions does not represent directly the number of
irregular migrants but is indicave of the number of
persons, which may add to the stock if not returned.
Figure 2: Number of uniform Schengen visas in 2016 by main countries where consulates issuing the visas
are located
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
Source: European Commission, Schengen visa stascs. Chart produced by the KCMD.
Note: The data do not necessarily reect the countries of origin of the people receiving the uniform Schengen visa.
Eurostat asylum and managed migration
Data on asylum and managed migraon are made
available by Eurostat on its database portal.15 These
data are supplied to Eurostat by the naonal ministries
of interior and related ocial agencies. Data on
rst-me asylum applicaons are disaggregated by
cizenship, age and sex, including unaccompanied
minors. As an example, Figure 3 shows the top 20
cizenships of asylum requests in EU–EFTA in 2016.
The data on the asylum procedure are not designed
to keep track of the same individuals across the enre
procedure but is capturing aggregate numbers for
administrave events at the dierent stages of the
procedure each year. There are no xed temporal
linkages between data of dierent years since the
lengths of the procedures may vary on an individual
basis and across countries.
15 See hp://ec.europa.eu/eurostat/web/asylum-and-
managed-migraon/data/database

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Figure 3: Top 20 countries of origin for asylum applicants in European Union–European Free Trade Associaon,
2016
Source: Map produced by the KCMD.
Note: Almost 30 per cent of the asylum seekers in 2016 came from the Syrian Arab Republic.
Figure 4: First-me asylum applicaons, total number of rst-instance decisions and negave rst-instance
decisions
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
2008 2009 2010 2011 2012 2013 2014 2015 2016
First-time asylum applications
Total first-instance decisions
Negative first-instance decisions
Source: Chart produced by the KCMD.
Note: First-instance rejecons data are a proxy of irregular migraon geographic and status ows.

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The main Eurostat data sets on enforcement of
immigraon legislaon that can be linked to irregular
migrant stocks and irregular migraon ows are
described below and exemplied in Figure 5.
• Third-country naonals refused entry at the
external borders (migr_eirfs): The data relate to
non-EU naonals formally refused permission to
enter the territory of an EU Member State. This
is not a direct measure of irregular migrants into
the EU; however, these data give an approximate
indicaon on the trends of irregular inows.16
• Third-country naonals found to be illegally
present (migr_eipre): The data refer to non-EU
naonals who are detected by Member States’
authories as illegally present under naonal
laws. The main limitaon in using such a data set
is linked to the fact that some countries include
irregular border crossing detecons and in this
way the data on irregular migrants are mixed with
the data on irregular migraon.
16 M. Jandl, “The esmaon of illegal migraon in Europe”,
Migraon Studies, March 2004:141–156.
• Third-country naonals ordered to leave (migr_
eiord) and third-country naonals returned
following an order to leave (migr_eirtn): The
rst data set includes non-EU naonals found
to be illegally present who are subject to an
administrave or judicial decision or act stang
that their stay is illegal and imposing an obligaon
to leave the territory of a Member State. The
second data set refers to persons who have, in fact,
le the territory of a Member State. The linkage
between the two data sets is not automac since
the enforcement of the order to leave may take
place in a subsequent year in respect of judicial
decision.
Figure 5: Data on third-country naonals refused entry at the external borders, found illegally present,
ordered to leave and returned following an order to leave in EU-28
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
2008 2009 2010 2011 2012 2013 2014 2015 20 16
EU-28 third-country nationals refused entry at the external borders
EU-28 third-country nationals found illegally present
EU-28 third-country nationals ordered to leave
EU-28 third-country nationals returned following an order to le ave
Source: Eurostat. Chart produced by the KCMD.
Note: The high values for third-country naonals found illegally present in 2015 and 2016 may be aributed to the inclusion of irregular
border crossings for several countries (cfr. Figure 1).

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Aggregaon at the EU level may be prone to double-
counng and also to variable coverage (historical
series may not cover all EU-28 over me) for a few of
the data sets above; therefore, the relevant data must
be treated with due care before considering them as
indicators for irregular migraon.
Conclusion
There are two dierent concepts of irregularity
relevant to migraon: the rst is relave to the way
of arrivals (ow); and the second, to a status of stay
in a country (stock). The two concepts are linked but
should not be confused.
In parcular, it is dicult to reconstruct the stock
of irregular migrants from the ows of irregular
migraon since the regular migraon channels may
be used for prolonged and irregular stay in the country
(e.g. visa overstaying), or vice versa, in which irregular
migraon may be used to enter a country in order to
acquire a legimate status (refugee).
There are no ocial data sets that measure directly
irregular migraon and irregular migrants in the EU.
However, there are several data sets that can be used
as proxies to provide esmates.
The main limitaons in using such data sets relate to
the following:
• aggregaon at the European level is prone to
double-counng and variable coverage;
• each data set refers to me periods that are
not aligned and capture dierent stages of
administrave process (e.g. me lag between
asylum decision and applicaon data); and
• most of the data collected refer to detected
irregular migrants and migraon while the real
stock of irregular migraon remains unknown.
A signicant contribuon is expected to come from
developments related to the EES that will register
entry and exit data of non-EU naonals crossing the
EU external borders.
Acknowledgements
The authors would like to acknowledge the helpful
comments and suggesons by Eurostat.
All the data sets menoned in this arcle are openly
accessible through dedicated Web portals. Several of
them are made available for query, visualizaon and
analysis via the KCMD Dynamic Data Hub17 used to
produce the gures in this paper. n
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17 See hps://bluehub.jrc.ec.europa.eu/migraon/app/