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Appendix 2: Definition and Notes

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From the Census:


A census of population was taken on the night of Sunday, 24 April 2016, in accordance with the Statistics (Census of Population) Order 2015 (S.I. No. 445 of 2015).

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 are 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.

Definition of census towns

Historically, census towns were defined as a cluster of fifty or more occupied dwellings where, within a radius of 800 metres, there was a nucleus of thirty occupied dwellings (on both sides of a road, or twenty on one side of a road) along with a clearly defined urban centre e.g. a shop, a school, a place of worship or a community centre. Census town boundaries were extended over time where there was an occupied dwelling within 200 metres of the existing boundary.

Small Areas(SAs)
Small Areas are a relatively recent geographic concept compiled by the National Institute of Regional and Spatial Analysis (NIRSA) on behalf of the Ordnance Survey Ireland (OSi) and in consultation with the CSO. They were designed as the lowest level of geography for the compilation of statistics in line with data protection guidelines and typically contain between 50 and 200 dwellings. A further constraint imposed when creating these new areas, was that they nested within Electoral Division boundaries. Finally, they are generally comprised either of complete townlands or neighbourhoods.

Daytime Working Population
As part of Census 2016 all workers resident in Ireland on Census Night were geo-coded to their place of work. For the purposes of this report the total persons at work in any particular town or city are known as the daytime working population. The term is used loosely in the sense that it includes night-shift workers, along with those who are resident in the area and who work from home. The figures for daytime working populations exclude those who failed to provide information on the location of their workplace, and those who indicated they had no fixed place of work.

The term commuter refers to those who commute away from home to work, and excludes those who work from home.

Private Household
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.
A permanent private household is a private household occupying a permanent dwelling such as a house, flat or bed-sit.

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.

Social class
The entire population is classified into one of the following social class groups (introduced in 1996) which are defined on the basis of occupation (coded using Soc90):

  • Professional workers
  • Managerial and technical
  • Non-manual
  • Skilled manual
  • Semi-skilled
  • Unskilled
  • All others gainfully occupied and unknown

The occupations included in each of these groups have been selected in such a way as to bring together, as far as possible, people with similar levels of occupational skill. In determining social class no account is taken of the differences between individuals on the basis of other characteristics such as education. Accordingly social class ranks occupations by the level of skill required on a social class scale ranging from 1 (highest) to 7 (lowest). This scale combines occupations into six groups by occupation and employment status following procedures similar to those outlined above for the allocation of socio-economic group. A residual category “All others gainfully occupied and unknown” is used where no precise allocation is possible.

Data on disability was derived from answers to questions 16 and 17 of the 2016 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.

In Census 2016, persons aged 15 years and over were asked 3 questions. The first question asked if a person had ceased their full time education. If they had answered ‘yes’, they were then asked the age at which it ceased. The second question 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. The final question asked what the main field of study of the highest qualification (excluding Secondary school qualifications) completed to date was.

Marital breakdown rate

The marital breakdown rate is calculated as the number of separated and divorced persons as a proportion of those who were ever married.

Usual Residence

The usually resident and present in the State on Census Night measure of the population, referred to throughout this report, was 4,689,921 in April 2016.

Other Defintions:

Rent burden

The Residential Tenancies Board (RTB) register contains information on all tenancies registered by landlords, both private and Approved Housing Bodies (AHB). Rent burden depends on the level of rent and the disposable income of tenants, where the household disposable income is defined as household gross income minus social insurance and taxes.

Medical Card Holders

This measure includes 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 considered in the means test. 

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)’ which can be accessed on the Eurostat website

Secondary income streams of farmers

Secondary, non-agriculture income includes from all NACE sectors except A011 (Growing of non-perennial crops), A012 (Growing of perennial crops), A013 (Plant propagation), A014 (Animal production) and A015 (Mixed farming).

From the Labour force survey

Participation, Employment and Unemployment Rates

The rates given in this release are based on the International Labour Organisation (ILO) classification. The Participation Rate is the number of persons in the labour force expressed as a percentage of the total population aged 15 or over. The Employment Rate is the number of employed aged 15 to 64 expressed as a percentage of the total population aged 15 to 64.

To ensure coherence with Unemployment Rates produced by Eurostat, the CSO changed the method of calculation of the Unemployment Rate as of Q2 2015. Prior to this, the Unemployment Rate was calculated as the number of unemployed expressed as a percentage of the total labour force aged 15 and over. The change introduced limits the labour force to persons aged 15-74 and this excludes a small number of persons aged 75 and over in employment from the total labour force used in the calculation. The overall impact of this change was minimal.

Note there may be slight differences to the figures presented in this release compared to previously published, this is due to rounding of figures.

From EU Statistics on Income and Living Conditions (SILC)

At risk of poverty rate 

This is the share of persons with an equivalised income below a given percentage (usually 60%) of the national median income.  The rate is calculated by ranking persons by equivalised income from smallest to largest and then extracting the median or middle value.  Anyone with an equivalised income of less than 60% of the median is considered at risk of poverty at a 60% level.

Deprivation rate

Households that are excluded and marginalised from consuming goods and services which are considered the norm for other people in society, due to an inability to afford them, are considered to be deprived. The identification of the marginalised or deprived is currently achieved on the basis of a set of eleven basic deprivation indicators:

  1. Two pairs of strong shoes
  2. A warm waterproof overcoat
  3. Buy new (not second-hand) clothes
  4. Eat meal with meat, chicken, fish (or vegetarian equivalent) every second day
  5. Have a roast joint or its equivalent once a week
  6. Had to go without heating during the last year through lack of money
  7. Keep the home adequately warm
  8. Buy presents for family or friends at least once a year
  9. Replace any worn out furniture
  10. Have family or friends for a drink or meal once a month
  11. Have a morning, afternoon or evening out in the last fortnight for entertainment

Individuals who experience two or more of the eleven listed items are considered to be experiencing enforced deprivation. This is the basis for calculating the deprivation rate.

Consistent poverty rate

The consistent poverty measure looks at those persons who are defined as being at risk of poverty and experiencing enforced deprivation (experiencing two or more types of deprivation).

An individual is defined as being in ‘consistent poverty’ if they are

  • Identified as being at risk of poverty and
  • Living in a household deprived of two or more of the eleven basic deprivation items listed above 

Gini coefficient

Describes the relationship between cumulative shares of the population (ranked according to the level of income from lowest to highest) and the cumulative share of total income received by them.

Gross income

Income details are collected at both a household and individual level in SILC.  In analysis, each individual’s income is summed up to household level and in turn added to household level income components to calculate gross household income.  The components of gross household income are:

Direct Income:


  • Employee income
  • Gross employee cash or near cash income
  • Gross non-cash employee income
  • Employer’s social insurance contributions
  • Gross cash benefits or losses from self-employment

Other direct income:


  • Value of goods produced for own consumption
  • Pension from individual private plans
  • Income from rental of property or land
  • Regular inter-household cash transfers received
  • Interests, dividends, profit from capital investments in unincorporated business
  • Income received by people aged under 16

Social Transfers:

  • Jobseekers related payments
  • Old-age payments (note that this includes all occupational pensions and other such social welfare payments to those aged 65 and over)

Family/children related allowances:

  • Maternity/paternity/adoptive benefit
  • Child benefit
  • One-parent family payment
  • Carers’ payments

Housing allowances:

  • Rent supplement
  • Household benefit package
  • Exceptional needs payments

Other Social transfers:

  • Survivor's benefits
  • Sickness benefits
  • Disability benefits
  • Education related allowances
  • Social exclusion not elsewhere classified

Household disposable income

Tax and social insurance contributions are also summed to household level and subtracted from the gross household income to calculate the total disposable household income.  The components of disposable household income are gross household income less:

  • Employer’s social insurance contributions
  • Regular inter-household cash transfer paid
  • Tax (including USC) on income and social insurance contributions
  • Tax deducted at source from individual private pension plans

Nominal income figures

Nominal income figures are included in this release.  

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 disposable household Income

Disposable household income is divided by the equivalised household size to calculate equivalised disposable 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.

From New Dwelling Completions

New dwellings

The principal data source for the New Dwellings Completions (NDC) is connections data provided to the CSO by ESB Network. More information here.

ESB connections are classified into four categories:

  • New dwelling completion: Recently constructed dwelling, where a dwelling is a self-contained unit of living accommodation.
  • Reconnection: A dwelling that has been reconnected to the ESB Network after a period of two years of disconnection.
  • UFHD: Connection to the ESB Network of previously completed dwellings in Unfinished/Ghost estates. A methodology was developed to identify houses which were complete in 2011 and were subsequently connected to the ESB Network. Although these dwellings may have required finishing to become available for use they are not new dwelling completions for the purposes of this publication. However, dwellings in Unfinished/Ghost estates which were not in a complete state in 2011 are included as new dwelling completions on connection to the ESB Network.
  • Non-dwelling: A building connected to the ESB Network through a domestic connection that is not constructed for residential use. 

The dwelling type is defined by the ESB Network and classified into three categories:

  • Single: If a single domestic dwelling or farm premises is to be connected to the ESB Network, Form NC21 must completed and the dwelling is defined as 'single'.
  • Scheme: If a new multi-unit development with two or more houses is to be connected to the ESB Network, Form NC12 must be completed and each dwelling is defined as 'scheme'.
  • Apartment: If a new multi-unit development with two or more apartments is to be connected to the ESB Network, Form NC12 must be completed and each dwelling is defined as 'apartment'.

From Geographical Profiles of Income in Ireland 2016

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. 

From Measuring Distance to Everyday Services in Ireland 2019

Average distance

Calculated from the shortest distances by road from residential dwellings to a set of everyday services. Based on a matching exercise involving:

  • the coordinates of dwellings enumerated in Census 2016
  • the coordinates of destination points for a set of everyday services
  • the road network from Ordnance Survey Ireland (OSi)


The map in this release is © Ordnance Survey Ireland. All rights reserved. License number 01/05/001.