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Background and Methodology

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The results presented in this release are based primarily on a data-linking exercise of two pseudonymised Central Statistics Office data sources:

  • The Person Income Register

  • The Census of Population Analysis dataset

With additional insights included by data-linking with three additional pseudonymised data sources

  • HSE Primary Care Reimbursement Service

  • Residential Tenancies Board Register

  • Student Universal Support Ireland

The linkage and analysis was undertaken by the CSO for statistical purposes in line with the Statistics Act, 1993 and the CSO Data Protocol [1].

Before using personal administrative data for statistical purposes, the CSO removes all identifying personal information including the PPSN. The Personal Public Service Number (PPSN) is a unique number that enables individuals to access social welfare benefits, personal taxation and other public services in Ireland. The CSO removes the PPSN and creates a pseudonymised Protected Identifier Key (PIK). The PIK is a unique and non-identifiable number which is internal to the CSO. Using the PIK enables the CSO to link and analyse data for statistical purposes, while protecting the security and confidentiality of the individual data. All records in the matched datasets are pseudonymised and the results are in the form of statistical aggregates which do not identify any individuals.

Data Sources 

Person Income Register (PIR) 

The PIR is a pseudonymised income register held internally within the CSO. It contains information on income received by individuals relating to employment, self-employment and social transfers. It is derived from administrative holdings held by the Revenue Commissioners and Department of Employment Affairs and Social Protection. Therefore, the PIR provides a near complete picture on individual level income, for a calendar year.  All linkage is carried out by using a PIK assigned on each contributing data source. The PIK is then used to link the pseudonymised data sources together in order to create the PIR. The PIK protects a person’s identity but also enables linking across data sources and over time. The PIK enables high quality deterministic matching thus significantly reducing/eliminating linkage error.

Census of Population Analysis (COPA)

The COPA is a pseudonymised copy of the Census of Population 2016 dataset held internally within the CSO for analysis purposes. It contains Census attribute information for individuals and households of which 95% of records have a PIK which allows them to be linked to pseudonymised administrative data sources to create new analysis. 

Primary Care Reimbursement Service (PCRS)

PCRS is responsible for making payments to healthcare professionals – doctors, dentists, pharmacists and optometrists/ophthalmologists – for the free or reduced costs services they provide to the public across a range of community health schemes. The schemes form the infrastructure through which the HSE delivers a significant proportion of Primary Care to the public. PCRS also manages the National Medical Card Unit (NMCU) which was established in 2011 to process all Medical Card and GP Visit Card applications at a national level.

Residential Tenancies Board (RTB) Registrar

The Residential Tenancies Board (RTB) register contains information on all tenancies registered by landlords, both private and Approved Housing Bodies (AHB).

Student Universal Support Ireland (SUSI)

Student Universal Support Ireland contains funding information for all higher and further education grants. SUSI offers funding to eligible students in approved full-time, third-level education in Ireland and also, in some cases, funding for students studying outside the State. It offers support to all types of students, from school leavers to mature students returning to education.

Reference period

All income data referenced in the publication spans the period from 1 January 2016 to 31 December 2016. The geographic and demographic variables, such as place of work and household status, were collected on Census reference day, 24th April 2016.

Target population

Individual income was compiled for the population aged 15 years and over identified as living in private households in Census 2016. A private household comprises either one person living alone or a group of people (not necessarily related) living at the same address with common housekeeping arrangements - that is, sharing at least one meal a day or sharing a living room or sitting room. In order to be included in the household, a person had to be a usual resident at the time of the Census. Therefore, visitors to the household on Census Night were excluded, while usual residents temporarily absent (for less than 12 months) were included.

Individuals and private households where place of work was identified as outside of the Republic of Ireland were excluded from any analysis.


Income missing from PIR

There were records in the PIR that could not be linked to COPA2016. The reasons for not being recorded on the COPA2016 include; absent persons identified in Census, persons living abroad but working or paid for work in Ireland, and persons who arrived in Ireland after or left Ireland before the 24 April 2016. This "missing" gross income came to a total €12.6 billion for 2016. This figure also includes income related to records which do not have a PIK on the COPA2016 dataset.


Gross income

The annual gross income before deductions such as tax and social insurance which was measured in nominal terms and includes:

  • Gross earnings from employment

  • Gross earnings from self-employment

  • Gross income from occupational pensions

  • Gross income from rent less allowable expenses

  • Social welfare income 

  • Income from higher & further education grants

Excluded from the income measure are:

  • Investment income, including saving accounts, bonds, stocks and shares

  • Income from foreign rental property

  • Community Employment Programme income

There was declared income of approximately €3.3 billion from these forms of income in 2016.

Income outputs are produced at individual and household level. Households were identified using information gathered in Census 2016. Since income may be pooled and shared to pay for expenses such as food and rent, it is often useful to look at the situation of a household by summing income for household members. The sources of household income are the same as for individual income and a similar distribution across sources is expected.

Income has been capped at €200,000 at individual level to remove the top 1% of income earners for confidentiality purposes.

Disposable income

Tax and social insurance contributions were estimated and summed to household level and subtracted from the household gross income to calculate the annual household disposable income, which was only used for the Rent Burden analysis. The components of household disposable income are household gross income less:

  • Employer’s social insurance contributions

  • Tax (including USC) on income or profit

  • Social insurance contributions

  • Tax deducted at source from individual private pension plans 

Earned income 

Annual gross earnings for 2016 from P35 employee income and IT form 11 self-employed trading income before deductions such as tax and PRSI from Revenue unadjusted for hours and/or weeks worked. 

Social welfare

Total annual payments from the Department of Employment Affairs and Social Protection(unless otherwise stated), catergorised into the following [2]:

  • Pensions including State Pension, Widow’s, Widower’s or Surviving Civil Partner’s Contributory Pension

  • Working Age Income Supports including Jobseeker’s Benefit, Jobseeker’s Allowance, One-Parent Family Payment, Widow’s, Widower’s or Surviving Civil Partner’s Non-Contributory Pension, Deserted Wife’s Allowance, Basic Supplementary Welfare Allowance, Farm Assist, Deserted Wife’s Benefit, Maternity Benefit, Paternity Benefit, Adoptive Benefit, Health and Safety Benefit, Redundancy Payments, Insolvency Payments

  • Working Age Employment Supports including Rural Social Scheme, Tús - Community Work Placement Initiative, Back to Work Enterprise Allowance, Short-Term Enterprise Allowance, Part-time Job Incentive Scheme, Working Family Payment, Back to Work Family Dividend, JobsPlus Incentive, Partial Capacity Benefit

  • Illness, Disability and Carers including Illness Benefit, Invalidity Pension, Disability Allowance, Blind Pension, Carer’s Allowance, Carer’s Support Grant, Carer’s Benefit, Domiciliary Care Allowance, Medical Care Scheme, Injury Benefit, Disablement Benefit, Constant Attendance Allowance, Incapacity Supplement, Death Benefit

  • Children including Child Benefit, Working Family Payment, Guardian’s Payment (Contributory), Guardian’s Payment (Non-Contributory), Back to School Clothing and Footwear Allowance, Widowed or Surviving Civil Partner Grant, Family Income Supplement

  • Supplementary Payments including Electricity Allowance, Gas Allowance, Free Television Licence, Fuel Allowance

No income

Individuals and households who were identified as living in Ireland in COPA but could not be linked to administrative income data in the PIR in 2016. 

Census Geography

Census Towns (Settlements)

In Census 2016, a new Census town was defined as there being a minimum of 50 occupied dwellings, with a maximum distance between any dwelling and the building closest to it, of 100 metres, and where there was evidence of an urban centre (shop, school etc). Town analysis in this report is limited to the 41 settlements with a population of 10,000 or greater. 

Counties and Cities

Under the Local Government Reform Act, 2001 (S.I. 591 OF 2001) the areas formerly known as County Boroughs are now called Cities.  Areas formally known as Municipal Boroughs are now called Boroughs.                                

The Local Government Reform Act 2014 Section 9 provided for the amalgamation of the city and county councils in Limerick and Waterford, and North Tipperary and South Tipperary County Councils. The newly amalgamated councils will be called Limerick City and County Council, Tipperary County Council and Waterford City and County Council.

In Census reports, the country is divided into 26 Counties/administrative counties and the five Cities.  Outside Dublin, there are 23 administrative counties and four Cities, i.e. Cork, Limerick, Waterford and Galway.  In Dublin, the four local authority areas are identified separately, i.e. Dublin City and the three Administrative Counties of Dún Laoghaire-Rathdown, Fingal and South Dublin.

Place of Work, School or College

As part of the Census 2016 processing programme places of work, school and college were geo-coded. All workers resident in Ireland on Census night were coded to their place of work and all Irish resident students from the age of 5 and upwards were coded to their place of school/college [3].

Electoral Divisions (EDs) 

There are a total of 3,409 EDs referred to in this report.

Electoral Divisions are the smallest legally defined administrative areas in the state. Previously known as District Electoral Divisions (DEDs), changed to Electoral Division by Section 23 of the Local Government Act, 1994 with effect from 24 June 1996.

DEDs began as subdivisions of poor law unions, grouping one or more townlands together to elect members to a Board of Guardians. The DED boundaries were drawn by a Poor Law Boundary Commission, with the intention of producing areas of roughly equal "rateable value" as well as population. EDs are mostly contiguous but may bear little relation to natural community boundaries.

Other Definitions

Family Units

A family unit or nucleus is defined as:

(1) a married couple or cohabiting couple; or

(2) a married couple or cohabiting couple together with one or more usually resident never-married children (of any age); or

(3) one parent together with one or more usually resident never-married children (of any age).

Family members have to be usual residents of the relevant household.

The determination of household and family composition is based on responses to the question on the census form dealing with relationships within the household.

Rent Burden

Rent from the pseudonymised RTB tenancies register for dwelling as a percentage of total household disposable income.


Data on disability was derived from answers to questions 16 and 17 of the Census questionnaire.  Question 16 was a seven-part question that asked about the existence of the following long lasting conditions: (a) blindness or a serious vision impairment, (b) deafness or a severe hearing impairment, (c) a difficulty with basic physical activities such as walking, climbing stairs, reaching, lifting or carrying, (d) an intellectual disability (e) a difficulty with learning, remembering or concentrating, (f) a psychological or emotional condition and (g) a difficulty with pain, breathing or any other chronic illness or condition. If a person answered YES to any of the parts of Q16, they were then asked to answer Question 17. This question was a four-part question that asked whether an individual had a difficulty doing any of the following activities: (a) dressing, bathing or getting around inside the home (self-care disability); (b) going outside the home alone to shop or visit a doctor’s surgery (going outside the home disability); (c) working at a job or business or attending school or college (employment disability) and (d) participating in other activities, such as leisure or using transport. Individuals were classified as having a disability if they answered YES to any part of the above two questions, including, in particular, if they ticked YES to any of the parts of Q17 even though they may not have ticked YES to any of the parts of Q16. The formats of these questions were updated in 2011 in consultation with users and interested groups.

Medical Card Holders

Medical Card Holders, excluding GP Visit Card Holders, under the General Medical Services (GMS) Scheme in 2016. A medical card issued by the Health Service Executive (HSE) allows the holder to receive certain health services free of charge. To qualify for a medical card your weekly income must be below a certain figure for your family size. Cash income, savings, investments and property (except for your own home) are taken into account in the means test. 


In Census 2016 persons aged 18 years and over were asked what was the highest level of education (full or part time) completed to date. The levels ranged from no formal education to a tertiary post doctorate degree. 

NACE Rev.2 Classification:

The economic sector classification (NACE) is based on the ‘Statistical Classification of Economic Activities in the European Community, Rev. 2 (2008)’ [4] which can be accessed on the Eurostat website. NACE codes were allocated accordingly as provided in P35 and IT form 11.


The Occupation classification used here and in Census 2016, is based on the UK Standard Occupational [5], with modifications to reflect Irish labour market conditions. 


All maps in this release are © Ordnance Survey Ireland. All rights reserved. License number 01/05/001.