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Background Notes

Background Notes

CSO statistical release, , 11am

This release is categorised as a CSO Frontier Series Output and is based on linking administrative income data with the 2022 Census population living in private households. When calculating household income, estimates for some households are underestimated, as not all income sources are included, such as undeclared employment income, inter-household transfers, and some foreign pensions. Throughout this release, the term administrative income will be used to describe the income sources covered.

Equivalised income allows for a more meaningful comparison of income across households by accounting for the number of adults and children living in the household, thus allowing for analysis at an individualised level. The term low-income threshold refers to households with an equivalised net administrative income of below 60% of the national median equivalised net income as derived from administrative data sources. In this release, the low-income threshold is deemed to be €16,271. 

As a CSO Frontier Series release, particular care must be taken when interpreting the statistics in this release as it may use new methods which are under development and/or data sources which may be incomplete, for example, new administrative data sources. For further information on the data sources, linking procedures and limitations of this report, see these Background Notes.

Data Sources

The results presented in this release are based on the Geographical Profiles of Income in Ireland 2022 - Household Income (GPII) dataset, which was a data-linking exercise of two pseudonymised Central Statistics Office data sources:

  • The Person Income Register (PIR) 2022
  • The Census of Population Analysis (COPA) 2022 dataset

With additional insights included by data-linking with two additional pseudonymised data sources:

  • Student Universal Support Ireland (SUSI)
  • Form 11
  • Irish Population Estimates from Administrative Data Sources (IPEADS)

Data Protection

The linkage and analysis was undertaken by the Central Statistics Office (CSO) for statistical purposes in line with the Statistics Act, 1993 and the CSO Data Protocol.

Before using personal administrative data for statistical purposes, the CSO removes all identifying personal information. This includes the Personal Public Service Number (PPSN), a unique number used by people in Ireland to access social welfare benefits, personal taxation, and other public services. A pseudonymised Protected Identifier Key (PIK) is created by the CSO when the PPSN is removed. This PIK is unique and non-identifiable and is only used by 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. For further information see Administrative Data FAQ.

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 Revenue and Department of Social Protection. Therefore, the PIR provides a near complete picture on individual level income, for a calendar year. 

Census of Population Analysis (COPA)

The COPA is a pseudonymised copy of the Census of Population 2022 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.

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.

Form 11 Income Tax returns (ITForm11)

The ITForm11 contains the annual income tax returns of the self-employed. Data for a calendar year is only complete three years after the reference year, because of the nature of self-assessment, although the majority of records are available about 14 months after the reference year. The ITForm11 was linked to for rental income.

Irish Population Estimates from Administrative Data Sources (IPEADS)

The CSO’s IPEADS 2022 features demographic estimates that are based on administrative records. It is important to note that such administrative records are designed for the operational needs of Irish public bodies and not as statistical data sources.

Reference Period

All income data referenced in the publication spans the period from 01 January 2022 to 31 December 2022.

The geographic and demographic variables were collected on Census reference day, 03 April 2022.

Target Population

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.

Usual residents who were enumerated outside of their place of usual residence, were as far as possible moved back to their place of usual residence. Enumerated persons that could not be matched to a place of usual residence were excluded. Persons usually resident in communal establishments are out of scope. Persons absent abroad on Census night are excluded, as are households that were fully absent on Census night. Private households of individuals where the place of work was identified as outside of the Republic of Ireland were excluded from any analysis.

From an initial population of 5,084,879 persons usually resident in Ireland and present on Census night, a total of 161,519 persons are excluded from analysis in the Income Analysis using Administrative Data Sources (IAADS) publication, resulting in a target population for the IAADS of 4,923,360 persons.

The number of private dwellings recorded on Census night, including permanent and non-permanent dwelling units as well as temporarily absent households, was 1,875,946. Excluding persons as listed above leaves a target household population for the IAADS of 1,824,262 dwellings.

Methodology

The COPA2022 dataset records where persons were enumerated on Census night. This may not have been their place of usual residence. For the purpose of producing household income and equivalised income statistics, persons not enumerated in their place of usual residence were moved back to their home as far as possible. It was not possible to re-locate all such persons. A combination of the Eircode PIK of the usual residence provided on the Census form and the Irish Population Estimates from Administrative Data Sources, 2022 dataset were used to return persons enumerated elsewhere to their place of usual residence. Those that could not be linked to a place of usual residence were excluded from analysis. Households fully occupied by persons that indicate their usual residence is elsewhere, are thus dropped and the residents moved to their place of usual residence where possible.

Persons who indicated that they worked outside of Ireland and had employment income on Irish administrative data totalling less than €10,000 were excluded from analysis, along with their household, as the household income records were deemed incomplete.

Persons not present in the state and enumerated on Census night are excluded from analysis.

These exclusions led to the removal of 51,684 households. The largest concentration of these was in border areas. Particular care should be taken with border area estimates, as illustrated in Table 4.1, where 27 of the 30 electoral divisions with the most dropped households were in Donegal, Monaghan, or Cavan. Also, after removing these households, many of these households were not matched to administrative income sources. Areas with high student populations are also liable to having a lower percentage of households matched with administrative income.

For further information see Tables 5.1 and 5.2 of the Geographical Profiles of Income in Ireland 2022 - Household Income - Background Notes.

Coverage

Missing data linkage Identifier

There are records on the COPA2022 dataset which do not have a PIK and thus cannot be linked with administrative income. For the target population of the IADDS, the PIK coverage for persons aged 15+ was 95.2%.

Income missing from IADDS

At the household level, 4.8% of households in the IADDS dataset were not matched to administrative income. The reasons for not being matched include: records which do not have a PIK on the COPA2022 and thus cannot be linked to administrative income; households with income sources not covered by the IADDS gross income definition; or households subsisting on savings or interhousehold transfers such as students.

Income missing from PIR

There were records in the PIR that could not be linked to COPA2022. The reasons for not being recorded on the COPA2022 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 03 April 2022. This "missing" gross income came to a total €20.4 billion for 2022. This figure also includes income related to records which do not have a PIK on the COPA2022 dataset.

Income

Gross household administrative 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 and private 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

Income outputs are produced at household level. Households were identified using information gathered in Census 2022.

Net household administrative income

Income tax, Universal Social Charge (USC) and social insurance contributions were estimated and summed to household level and subtracted from the household gross income to calculate the annual household net income. The components of household net income are household gross income less:

  • Tax (including USC) on income or profit
  • Social insurance contributions

Social welfare

Total annual payments from the Department of Social Protection (unless otherwise stated), categorised into the following:

  • Pensions including State Pension, Widow’s, Widower’s, or Surviving Civil Partner’s Contributory Pension.
  • Working Age Income Supports including COVID-19 Pandemic Unemployment Payment (PUP), Jobseeker’s Benefit, Jobseeker’s Allowance, One-Parent Family Payment, Widow’s, Widower’s or Surviving Civil Partner’s Non-Contributory Pension, Basic Supplementary Welfare Allowance, Deserted Wife’s Benefit, Maternity Benefit, Paternity Benefit, Adoptive Benefit, Health and Safety Benefit.
  • Working Age Employment Supports including Back to Work Allowance, Part-time Job Incentive Scheme, Partial Capacity Benefit.
  • Illness, Disability and Carers including Invalidity Pension, Disability Allowance, Blind Pension, Carer’s Allowance, Carer’s Benefit, Domiciliary Care Allowance, Medical Care Scheme, Injury Benefit, Disablement Benefit, Constant Attendance Allowance.
  • Children including Child Benefit, Working Family Payment, Guardian’s Payment, Back to School Clothing and Footwear Allowance, Widowed or Surviving Civil Partner Grant.
  • Higher and further education grants including Student Universal Support Ireland (SUSI).
  • Rent supports including Rent Supplement, Housing Assistance Payment (HAP).
  • Other supports including the Households Benefits Package, Fuel Allowance, and supports not classified elsewhere.

No administrative income

Individuals and households who were identified as living in Ireland in the COPA but could not be linked to administrative income data in the PIR in 2022.

Households with no administrative income are excluded from estimates of means and median household income. The only tabulations in this publication where they included are in the distribution of household income graph and associated tables.

Calculation of mean and median household income

For the calculation of mean and median household income, households with no administrative income are excluded.

Mean: Sum of all household income, divided by the number of households with administrative income. e.g. The mean of the following four household incomes {€0, €18,000, €45,000, €70,000} is, after dropping the household with no administrative income, (18,000+45,000+70,000)/3 = €44,333.

Median: Midpoint of the ordered values, after removing households with no administrative income. e.g. The following four household incomes {€0, €18,000, €45,000, €70,000}, after dropping the household with no administrative income, becomes {€18,000, €45,000, €70,000}. The median of which is €45,000.

Equivalence scales

Equivalence scales are used to calculate the equivalised household size in a household. Although there are numerous scales, we focus on the national scale in this release. The national scale attributes a weight of 1 to the first adult, 0.66 to each subsequent adult (aged 14+ living in the household) and 0.33 to each child aged less than 14. The weights for each household are then summed to calculate the equivalised household size.

Equivalised net administrative income

Net household administrative income is divided by the equivalised household size to calculate equivalised net administrative income for each person, which essentially is an approximate measure of how much of the income can be attributed to each member of the household. This equivalised income is then applied to each member of the household.

Low administrative income threshold

Persons with an equivalised net administrative income below 60% of the national median equivalised net administrative income are deemed to be below the low administrative income threshold.

Comparability

Geographical Profiles of Income in Ireland (GPII) 2016

The GPII 2022, and by extension the IAADS 2022, is not directly comparable to the 2016 GPII publication due to methodological changes. The primary change is that the 2016 GPII was based on where persons were enumerated on Census night, whereas the 2022 GPII persons enumerated outside of their usual residence were returned to their place of usual residence as much as possible. Also the 2022 GPII includes income from HAP, which the 2016 edition did not.

Survey on Income and Living Conditions (SILC)

SILC is the official source of household income and at risk of poverty statistics in Ireland. However, SILC is a sample survey is a sample survey and cannot go into the level of geographic detail that the IAADS can. The calculation of household income is not comparable between the two as the methodologies differ significantly. The IAADS is limited to the use of administrative income in the calculation of gross, while SILC includes additional components such as:

  • Rent a room rental income
  • Regular inter-household cash transfers received
  • Interests, dividends, profit from capital investments in unincorporated business
  • Foreign social transfers
  • Employer’s social insurance contributions and pension contributions

Classifications

Census Reference Person

On the 2022 Census file, the reference person in each private household is the first person in the household identified as a parent, spouse, cohabiting partner or head of a non-family household containing related persons. Where no person in the household satisfied these criteria, the first usually resident person was used as the reference person. In this publication, the reference person is referred to as the ‘head of household’.

Ethnicity

Data on ethnicity was taken from Census 2022. The question on ethnic group or background was updated for Census 2022 with new response categories added including Roma, Indian/Pakistani/Bangladeshi and Arab.

Question 11 on Census 2022 persons form asked “What is your ethnic group/background?”, with response options:

  • A: White:
    • 1 Irish
    • 2 Irish Traveller
    • 3 Roma
    • 4 Any other White background (with a write-in box)
  • B: Black or Black Irish:
    • 5 African
    • 6 Any other Black background (with a write-in box)
  • C: Asian or Asian Irish:
    • 7 Chinese
    • 8 Indian/Pakistani/Bangladeshi
    • 9 Any other Asian background (with a write-in box)
  • D: Other, including mixed group/background:
    • 10 Arabic
    • 11 Mixed, write in description
    • 12 Other, write in description

For further information on Census 2022 questions see Census 2022 Household Form Questions.

For household level income analysis by ethnicity, the ethnicity refers to that of the head of household.

General Health

Data on self-perceived general health was taken from Census 2022. People were asked to rate their general health on a five-point scale from very good to very bad.

Question 17 on Census 2022 asked “How is your health in general?”:

  • Very good
  • Good
  • Fair
  • Bad
  • Very bad

Long-lasting Condition or Difficulty

Data on long-lasting condition or disability was taken from the 2022 census. This was derived from answers to Questions 15 and 16 of the census questionnaire. Question 15 was a seven-part question that asked about the existence of the following long lasting conditions: (a) blindness or a vision impairment, (b) deafness or a 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 or a mental health issue and (g) a difficulty with pain, breathing or any other chronic illness or condition. Respondents had the option to indicate that they did not have any of these long-lasting conditions, had one or more of them to some extent, or had one or more of them to a great extent.

Question 16 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. As with Question 15, respondents could indicate that they had no difficulty with any of these activities, that they had some difficulty or that they had a lot of difficulty. Question 16 on day-to-day difficulties specifically included difficulties caused by old age.

For the publication of the results, three categories were created based on the response options in Q15 and Q16. These are as follows:

  • Long-lasting condition or difficulty experienced to any extent
  • Long-lasting condition or difficulty experienced to some extent
  • Long-lasting condition or difficulty experienced to a great extent

Respondents who ticked any of the 'Yes' boxes in Q15 or Q16 were also included in the 'disability to any extent' rate.

Respondents who ticked at least one of the boxes for 'Yes, to some extent' in Q15 or 'Yes, a little' in Q16 but did not tick any of the 'Yes to a great extent' in Q15 or 'Yes, a lot' in Q16 were used as part of the calculation of the 'Long-lasting condition or difficulty experienced to some extent' category.

Respondents who ticked at least one of the 'Yes, to a great extent' boxes in Q15 or 'Yes, a lot' boxes in Q16 were used as part of the calculation of the 'Long-lasting condition or difficulty experienced to a great extent' category. For further information see Background Notes Census of Population 2022 Profile 4 - Disability, Health and Carers.

Working-age household

Working-age households, as defined in this publication, are those that contain at least one working-age person. A working-age person is defined here as a person aged 18-64, excluding: students aged 18-24; retired persons; and persons aged 60-64 who are not working and where the majority of household income is from pensions.

Carers

In this publication, carers are defined as persons in in receipt of carer’s allowance or carer’s benefit from the Department of Social Protection (DSP). DSP administrative data is utilised to identify such persons for 2022.

Census Geography

Administrative counties

Administrative Counties correspond with the Local Authorities, covering 31 city and county councils. For example, Cork County refers to the region administered by Cork 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: Cork, Limerick, Waterford, and Galway. In Dublin, the four local authority areas are identified separately: Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin. For further information, see CSO Geographical classifications - national level.

Towns/Urban Areas also known as Built Up Areas (BUAs)

For Census 2022, the Central Statistics Office introduced a new way of defining urban areas, Built Up Areas (BUAs). Where the word 'town' is used in this release, it is referring to the BUAs with a population of least 1,500 persons. For more information about BUAs, please see Census 2022 Urban Settlement Boundaries and Built Up Areas

Local Electoral Areas (LEAs)

For the purposes of Local Authority elections, each county and city is divided into Local Electoral Areas (LEAs) which are constituted on the basis of Orders made under the Local Government Act, 1941. Statutory Instruments 610-638 of 2018 and 6-8, 27-28, 156-157 of 2019 state the current composition of LEAs and their subsequent amalgamation into Municipal Districts.

In general, LEAs are formed by aggregating Electoral Divisions. However, in a number of cases, Electoral Divisions are split between LEAs and in order to render them suitable for production of statistics, the CSO has amended some LEA boundaries to ensure that statistical disclosure does not occur. As a result of these amendments, Census 2022 LEAs are comprised of whole Census 2022 Electoral Divisions.

For further information see Census 2022 Small Area Population Statistics

HSE Geography

 The new HSE health geographies are hierarchical. Just as counties nest within provinces, the 20 HSE Integrated Healthcare Areas (IHAs) nest within the 6 HSE Health Regions.

HSE Health Region (HR)HSE Integrated Health Area (IHA)
Table 6.1 HSE health regions and integrated health areas
HSE Dublin and Midlands HR HSE Dublin South City and West IHA
HSE Dublin South West IHA
HSE Kildare West Wicklow IHA
HSE Midlands IHA
HSE Dublin and North East HR HSE Cavan Monaghan IHA
HSE Dublin North City and West IHA
HSE Dublin North County IHA
HSE Louth Meath IHA
HSE Dublin and South East HR HSE Carlow Kilkenny and Tipperary South IHA
HSE Dublin South and Wicklow IHA
HSE Waterford Wexford IHA
HSE Midwest HR HSE Clare and Limerick County IHA
HSE Limerick City and Tipperary North IHA
HSE South West HR HSE Cork North and East IHA
HSE Cork South and West IHA
HSE Kerry IHA
HSE West and North West HR HSE Donegal IHA
HSE Galway Roscommon IHA
HSE Mayo IHA
HSE Sligo Leitrim IHA

For further information see HSE health regions