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Background Notes

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Appendix 1

Background Notes

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)

Coverage of the Census

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 on the night of Sunday, 24 April 2016, together with all persons who arrived in that area on the morning of Monday, 25 April 2016, not having been enumerated elsewhere.  Persons on board ships in port are included with the population of adjacent areas. 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.

De facto versus Usual Residence

The date of the census was chosen to coincide with a period when passenger movements were at a minimum and, consequently, the figures closely approximate to those for the normally resident population. The de facto measure of the population, referred to throughout this report, was 4,761,865 in April 2016 while the usually resident and present total was 4,689,921, a difference of 71,944 or 1.5%. The usually resident measure is used when analysing topics such as nationality and households and families.

Conduct of the Census

A temporary field force consisting of 6 Census Liaison Officers, 44 Regional Supervisors, 430 Field Supervisors and some 4,663 part-time enumerators carried out the census enumeration. During the four weeks before Census Night the enumerators visited some 2 million private residences and delivered census questionnaires to 1.7 million of these dwellings as well as to 4,140 communal establishments capable of accommodating people (such as hotels, nursing homes, etc.,) that were expected to be occupied on census night. Approximately 250,000 residences were vacant at the time of the census, while in the remaining cases the household was either enumerated elsewhere or temporarily absent from the State. The collection of completed questionnaires took place between Monday 25 April and Sunday 22 May, 2016.

The Central Statistics Office (CSO) wishes to record its appreciation of the public-spirited co-operation received from households and the work carried out by the census field force.

Production of results

Each enumerator first prepared and returned to the CSO a summary of the population of his/her enumeration area. These summaries formed the basis for the preliminary 2016 census results published in July 2016. The completed questionnaires for individual households were subsequently transported to the CSO for processing. The population summaries, dwelling listings and enumeration maps for individual enumeration areas were checked for consistency and used to determine the boundaries of census towns and suburbs. The capture and processing of the responses to questions on the questionnaires proceeded concurrently.

The planned publication schedule is contained in Appendix 3. Two summary reports will present highlight results primarily for the State; Census 2016 Summary Results - Part 1, looks at overall population change by county; it also examines age, marriage, households and families as well as including first results on nationality, foreign languages, the Irish language, religion and housing. The second summary report, Census 2016 Summary Results - Part 2, looks at other social and economic factors such as employment, occupations, education and skills as well as travel and health-related topics. A further seven profile reports will provide more detailed results on individual topics; the details are listed in the publication schedule.


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

Appendix 2


Urban and Rural Areas

The term Aggregate Town Area or Urban Area refers to settlements with a total population of 1,500 or more.  The term Aggregate Rural Area refers to the population outside Aggregate Town Areas and includes the population of settlements with a population of less than 1,500 persons.

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.

In 2011 the proximity criteria were tightened, in line with UN criteria. This was done in order to avoid the agglomeration of adjacent towns caused by the inclusion of low density one off dwellings on the approach routes to towns.

First introduced in 2011 therefore, and continuing for Census 2016, a new census town was defined as having 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.). The 100m proximity rule was also applied when extending existing 2011 Census town boundaries. 

Private Household

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.

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

temporary private household is a private household occupying a caravan, mobile home or other temporary dwelling.

Size of Household

The number of persons in a household consists of the total number of persons usually resident there on the night of Sunday, 24 April 2016, including those absent from the household for less than 12 months. Visitors present in the household on census night are excluded.

Household Reference Person

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.

For the purposes of expressing the household reference person in simple terms for the reader, the terms head of household or householder are sometimes used instead of the household reference person in this report.

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.

Family Cycle

The following classification is used for family units:

Pre-family: Family nucleus of married or cohabiting couple without children where female is under 45 years;

Empty-nest: Family nucleus of married or cohabiting couple without children where female is aged between 45 and 64 years;

Retired: Family nucleus of married or cohabiting couple without children where female is aged 65 years and over;

Pre-school: Family nucleus where oldest child is aged 0-4 years;

Early-school: Family nucleus where oldest child is aged 5-9 years;

Pre-adolescent: Family nucleus where oldest child is aged 10-14 years;

Adolescent: Family nucleus where oldest child is aged 15-19 years;

Adult: Family nucleus where oldest child is aged 20 years and over

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):

  1. Professional workers
  2. Managerial and technical
  3. Non-manual
  4. Skilled manual
  5. Semi-skilled
  6. Unskilled
  7. 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.

Appendix 3

Census 2016 Publication Schedule                                                                           


Publication Date

Preliminary Results                                

14 July 2016

Census 2016 Summary Results - Part 1              

06 April 2017

Profile 1 - Housing in Ireland                    

20 April 2017

Profile 2 - Population Distribution and Movements  

11 May 2017

Census 2016 Summary Results - Part 2              

15 June 2017

Profile 3 - An Age Profile of Ireland              

06 July 2017

Small Area Population Statistics (SAPS)          

20 July 2017

POWSCAR - Research micro data file                

20 July 2017

Profile 4 - Households and Families                

27 July 2017

Profile 5 - Homeless Persons in Ireland            

10 August 2017

Profile 6 - Commuting in Ireland                  

31 August 2017

Profile 7 - Migration and Diversity                

21 September 2017

Profile 8 - Irish Travellers, Ethnicity and Religion

12 October 2017

Profile 9 - Health, Disability and Carers        

02 November 2017

Profile 10 - Education, Skills and the Irish Language

23 November 2017

Profile 11 - Employment, Occupations and Industry  

14 December 2017


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