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Background Notes

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The reference period for the population estimates is the end of April of each year. The migration flows are in respect of the twelve months to end April, while the births and deaths are for the 12 months ending Q1 of the reference year. The usually resident population classified by age and sex for 2016 are taken from the Census of Population.

Usual residence population concept

For the purpose of this release the population concept of usual residence has been used, i.e. all persons usually resident and present in the State on census night plus absent persons who are usually resident in Ireland but are temporarily away from home and outside the State on census night. All persons are classified according to their region of usual residence.  Up to and including 2005, the de facto population concept was used.


De facto population concept - The census figures relate to the de facto population i.e. the population recorded for each area represents the total of all persons present within its boundaries census night, together with all persons who arrived in the area the following morning having not having been enumerated elsewhere.  The figures, therefore, include visitors present on Census Night as well as those in residence, while usual residents temporarily absent from the area are excluded.

Natural Increase - the natural increase is the difference between the number of births and the number of deaths recorded over a period.

Immigration - means the action by which a person establishes his or her usual residence in the State for a period that is, or is expected to be, of at least 12 months, having previously been usually resident in another Member State or a third country.

Emigration - means the action by which a person, having previously been usually resident in the State, ceases to have his or her usual residence in the State for a period that is, or is expected to be, of at least 12 months.

Net Migration - the difference between immigration into and emigration from the State during the reference period.

Principal source of Migration data 

The principal source of information for the estimation of the gross annual migration flows is the Irish Labour Force Survey (LFS), which also provides the basis for the classification of the flows by sex, age group, origin/destination and nationality.

The release also provides estimates of immigration and emigration by educational attainment (Table 1.6) and principal economic status (Table 1.7), based on responses in the LFS.  The principal economic status question refers to persons aged 15 years or over and is a self-perception question, i.e. people are classified according to how they perceive their situation.

As with all breakdowns of migration (by age, nationality, origin and destination), the breakdown by educational attainment and principal economic status should be considered broadly indicative given the relatively small sample sizes associated with these flows. In addition, as a person's principal economic status can change over the course of a year (and to a lesser extent their educational attainment), for immigrants these two tables refer to their status in the quarter prior to the April of the year in question, while for emigrants it is their status in the period prior to departure.

Effect of COVID-19 on the collection of migration data from the Labour Force Survey (LFS)

The LFS usually consists of a household being interviewed face-to-face initially while the majority of follow up interviews are conducted over the telephone.  The CSO had to suspend direct face-to-face interviews for the LFS (and other household surveys) due to the social distancing measures introduced in Ireland because of COVID-19. The CSO interviewer now sends an introductory letter to the household before the first interview, to explain the purpose of the survey and to arrange a suitable time for a phone call to conduct the initial LFS interview.

The Social Data Collection team in the CSO are actively engaged in mitigating against the impact of COVID-19 on LFS response rates and the CSO’s Methodology Division are providing guidance in relation to the weighting, calibration, non-response adjustment and other relevant methodology required for the LFS due to COVID-19.

Other sources of migration data

The migration estimates are compiled with reference to movements in other migration indicators such as the number of Personal Public Service (PPS) numbers allocated to non-Irish nationals.  Typically between 60% - 70% of non-Irish nationals issued with a PPSN in a given year, remain active the year following issue.

PPSN's issued to non-Irish nationals
  Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Total
2018 10,217 9,592 8,743 9,970 10,424 9,851 11,092 11,254 11,387 12,332 10.982 7.203 123,047 
2019 10,212 10,210 10,357 9,687 10,557 8,750 11,273 9,858 11,972 12,122 12,339 8,427  125,764 
2020 10,050 10,130 6,186 2,887 3,963  3,428 3,294  2,987  3,244  3,815  8,166  10,764  68,914 

Stocks of residence permits issued to 3rd country nationals are also examined for coherence purposes (see table below).  Note that while residence permits are generally required for those aged 15 years and over, the population stock of 3rd country nationals in the estimates applies to all ages.

Total stock of residence permits for 3rd country nationals - required for persons aged 15 and over
  2016 2017 2018 2019 2020
Total Stock 110,927 128,066 142,286 168,297 155,317

The number of visas issued to Irish nationals to a number of destinations including Australia, USA and Canada are compared with the emigration data collected by the LFS.  In addition, data on National Insurance numbers (equivalent to PPS numbers) issued to Irish nationals in the UK is also examined.

Calculation of annual population estimates

The annual population estimates for April are calculated by trending forwards the previous Census of Population data. For example, the base population data for estimating the April 2017 figure was the number of males and females in each region by single year of age and nationality as established by the 2016 Census. From this base, each person was aged by one year, births for the period were added and deaths were subtracted. The estimated number of immigrants was then added and the number of emigrants was subtracted. Allowance was also made for estimated inter-regional migration in arriving at the final 2017 figures.

The end result of this overall process provided the population estimate for April 2017 which in turn will provide the base population for the subsequent year and so on. The population estimates are subject to revision once the definitive results of the next census become available.

The population by nationality estimates are made possible by trending forwards the previous Census of Population and incorporating gross migration flows by nationality based on responses in the LFS. Allowance is also made for the non-Irish nationals who acquire citizenship certificates over the period in question. The number of births by nationality is estimated using the distribution of the nationality of births as recorded in the 2016 Census, while deaths by nationality are also estimated based on recent census results using the nationality distribution of the population by five year age groups.

Natural Increase 

The General Registration Office (GRO) supplies registered data for births and deaths and the latest available births and deaths are added to the population file quarterly.

Internal migration

By examining a person's usual residence at the time of a census and one year previously it is possible to determine inter-regional migration patterns. Following each Census a new internal migration matrix is produced and used to measure inter-censal internal migration. Internal migration for the year to April 2020 takes account of the Census 2016 results.

Census 2016 - Inter-regional internal migration flows
  Border Dublin Mid-East Midland Mid-West South-East South-West West State
Inwards 4,207 14,330 12,148 4,796 5,094 5,355 5,501 5,736 57,167
Outwards 3,691 18,716 10,282 4,052 5,185 4,344 5,470 5,427 57,167
Net Flow 516 -4,386 1,866 744 -91 1,011  31 309 0


All persons with Irish nationality or citizenship are classified under the category "Irish" in table 9 (Estimated population classified by sex and nationality).

The Irish Naturalization and Immigration Service provide annual data for persons who acquire Irish citizenship. The availability of the citizenship data for year N is N+2 and so estimates for 2018 and subsequent years will be achieved by trending forward the rates noted for the most recent year available.  Therefore, for the purpose of the 2020 release the 2018 distribution of citizenship acquisitions was applied.

 Citizenship Certificates issued
  2012 2013 2014 2015 2016 2017 2018 2019
UK 85 55 51 54 98 529 687 665
Rest of EU 14  75 91 149 145 170  169  202 133
EU 15 to 27 1,265 1,615 2,725 2,921 3,058  3,022  3,024 2,012
Rest of World 23,685 22,482 18,177 10,443 6,712  4,474  4,310 2,981
Total 25,110 24,243 21,102 13,563 10,038  8,196  8,223 5,791


NUTS2 and NUTS3 Regions

The Nomenclature of Territorial Units for Statistics (NUTS) were created by Eurostat in order to define territorial units for the production of regional statistics across the European Union. In 2003 the NUTS classification was established within a legal framework (Regulation (EC) No 1059/2003).

As the administrative territorial breakdown of EU Member States is the basis of the NUTS classification, changes made under the 2014 Local Government Act prompted a revision to the Irish NUTS 2 and NUTS 3 Regions. These changes included the amalgamation of the local authorities of Tipperary North and South, Limerick City and County Councils and Waterford City and County Councils. In addition three Regional Assemblies were established (Northern & Western, Southern, Eastern & Midland).

The main changes at NUTS 3 level are the transfer of South Tipperary from the South-East into the Mid-West NUTS 3 region and the movement of Louth from the Border to the Mid-East NUTS 3 Region. There are now three NUTS 2 Regions which correspond to the Regional Assemblies established in the 2014 Local Government Act and are groupings of the new NUTS 3 Regions. The revisions made to the NUTS boundaries have been given legal status under Commission Regulation (EU) 2016/2066. The new NUTS 2 and NUTS 3 structure and classification are displayed in the table below:

NUTS2 Code

NUTS 2 Name

NUTS3 Code

NUTS 3 Name



Northern & Western































Eastern & Midland 

















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