The linkage and analysis was taken by CSO for statistical purposes under the Statistics Act 1993 and the CSO Data Protocol [1], and follows the international standard of statistical production outlined in the Generic Statistical Business Process Model (GSBPM) [2].
As part of changes to the fieldwork first implemented in Census 2011 and continued for Census 2016, each household and dwelling was linked to geographical coordinates. This linkage has the benefit of offering flexibility in the production of census outputs for both existing and new boundaries, provided they are available in digital format.
In the case of 98% of dwellings on the Census 2016 geography dataset, this linkage was achieved through using the national address database as the basis to conduct the enumeration of dwellings. The remaining 2% of dwellings enumerated was retrospectively digitised by census staff according to the location marked by enumerators on paper maps during census fieldwork activities.
The national mapping database (called PRIME 2) [3] is maintained by OSi and contains over 50 million attributed objects represented as either a point, line or polygon. Each object has a form and function classification which describes the physical form (e.g. building) and its use (e.g. residential, hospital, church etc.). There are over 1,000 different function types recorded in PRIME 2. OSi gives access to the PRIME 2 database to public authorities for free under the National Mapping Agreement [4]
The central premise behind PRIME 2 is the ‘skin of the earth’ concept where topologically consistent objects cover the entire surface of the State. These objects are grouped into five broad categories; Way, Water, Vegetation, Artificial and Exposed (non-vegetative ground such as sand and mud).
The road network used to produce the results in this publication are the centrelines of objects classified as ‘Way’ in the PRIME 2 database, and which has been simplified to international standards as Geographic Data Files level 2 (GDF2). A ‘Way’ is a generic term to describe all roads, streets, paths, and footpaths, while GDF2 are ‘Way’ segments simplified along certain parts of the network (i.e. around motorways, dual carriageways and roundabouts). There are over 300,000 distinct segments in the ‘Way’ GDF2 dataset, where each segment is a piece of the road network from one junction to the next. Each segment is seamless and forms part of a connected set of continuous segments with no unbroken lines or edges.
All road segments were treated equally, which means that the distances calculated by the routing algorithm reflect the ‘shortest-path’ route and not the ‘optimum-path’ route. The ‘optimum-path’ approach involves weighting the road network segments using additional attributes such as road type, speed limits, whether the road is one-way etc. In addition, the road network covers the jurisdiction of the State only.
An exercise to map the border crossings on the public road network between Ireland and Northern Ireland was undertaken by the Department of Transport, Tourism and Sport in collaboration with the Department for Infrastructure, Northern Ireland. The results of this exercise were published in May 2018. Note that this publication examined border crossings between public roads across both jurisdictions
The coordinates of the public border crossings can be downloaded under Open Data license [5] at the following link:
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 nights of Sunday, 10 April 2011 and 24 April 2016, together with all persons who arrived in that area the following morning, 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.
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.
A temporary private household is a private household occupying a caravan, mobile home or other temporary dwelling.
The housing stock is defined as the total number of permanent residential dwellings that were available for occupancy at the time of census enumeration. In this report, the housing stock consists of permanent private households (inhabited by both usual residents and visitors), holiday homes, vacant houses or apartments along with dwellings where all the occupants were temporarily absent on Census Night. However, communal establishments, temporary private households (e.g. caravans and mobile homes), along with dwellings categorised by the enumerators as being derelict, commercial only, or under construction are excluded from this definition.
In identifying vacant dwellings, enumerators were instructed to look for signs that the dwelling was not occupied e.g. no furniture, no cars outside, junk mail accumulating, overgrown garden etc., and to find out from neighbours whether it was vacant or not. It was not sufficient to classify a dwelling as vacant after one or two visits. Similar precautions were also taken before classifying holiday homes.
Holiday homes are categorised as dwellings that are only occasionally occupied. While they are mainly found in rural areas (particularly along the coastline), holiday homes could also consist of city apartments used for weekend breaks etc. Before indicating that a dwelling was a holiday home, enumerators were instructed to call to the dwelling several times prior to Census Night and at various call times. Enumerators were advised to consult with neighbours as to whether a dwelling was used as a holiday home.
When the enumerator had clear information that a dwelling was used as a holiday home the dwelling status was recorded as “Holiday home” in their enumerator record book (ERB).
Dwellings under construction and derelict properties were not included in the count of vacant dwellings. As a result the empty housing units were classified as vacant house, vacant apartment or holiday home only if the dwelling was considered fit for habitation by the enumerator. In the case of newly constructed dwellings, that meant that the roof, doors, windows or walls had to be completely built or installed. For older dwellings that were unoccupied the roof, doors and windows had to be fully intact.
The results of the Quarterly National Household Survey (QNHS) provide the basis for the official series of quarterly labour force estimates. The labour force and its constituent figures shown in this report are directly based on the census. Users should be aware that information derived from identical questions in the census and QNHS for the same year may show appreciable differences. The main categories affected are the constituents of the question on principal economic status and the employment estimates classified by industry and occupation.
The main reasons for the differences are:
• The QNHS uses the International Labour Organisation (ILO) classification, which has a much wider range of questions on the labour force and which may have a bearing on the responses received to individual questions. Under the ILO criteria, employment, unemployment and inactive population are defined as follows:
• In Employment: Persons who worked in the week before the survey for one hour or more for payment or profit, including work on the family farm or business and all persons who had a job but were not at work because of illness, holidays etc. in the week.
• Unemployed: Persons who, in the week before the survey, were without work and available for work within the next two weeks, and had taken specific steps, in the preceding four weeks, to find work.
• Inactive Population (not in labour force): All other persons.
• The census form is completed by a responsible adult in each household throughout the State in respect of everyone present in the household on Census Night while the QNHS is by face to face interview.
• The census relates to all persons present in the State (including visitors from abroad) at the time of the census while the QNHS covers persons usually resident in Ireland.
• The census is a complete enumeration while the QNHS is a sample survey.
The chief difference resulting from this is that the census in 2016 records an unemployment rate (based on Principal Economic Status) of 12.9 per cent. Notwithstanding these differences, the main strength of the census-based data on employment and unemployment is the provision of data for small geographic areas, analysis on the comparisons between areas, the provision of data on unemployment blackspots, and other analysis across multiple variables such as marital status, detailed nationality, etc.
In Census 2011 and 2016, industry is coded using NACE – the General Industrial Classification of Economic Activities within the European Communities. The current version, NACE Rev. 2, is a 4-digit activity classification that was first used in Census 2011 and is a revision of the version originally published by Eurostat in 1970. The previous version, NACE Rev. 1, was in use in the censuses of 2002 and 2006.
NACE Rev. 2 is a hierarchical classification, with 88 Divisions at 2-digit level, 272 Groups at 3-digit level and 615 Classes at 4-digit level. Further information on the NACE Rev.2 classification is available on the CSO website.
Since the 2011 census a settlement is defined as being a cluster of 50 or more 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 criteria for extending an existing settlement depends on whether there are newly created estates or dwellings within 100 metres of the original settlement boundary. The delineation of settlements is conducted following the processing of census results i.e. every five years.
In Census reports, the country is divided into 31 administrative areas. Outside Dublin, there are 25 administrative counties and two Cities, i.e. Cork 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.
[2] Generic Statistical Business Process Model
[3] PRIME2 Client Documentation (PDF) (osi.ie)
[4] National Mapping Agreement (osi.ie)
[5] Open Data Licence (data.gov.ie)
Learn about our data and confidentiality safeguards, and the steps we take to produce statistics that can be trusted by all.