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CSO Frontier Series outputs may use new methods which are under development and/or data sources which may be incomplete, for example new administrative data sources. Particular care must be taken when interpreting the statistics in this release.
Learn more about CSO Frontier Series outputs.
Irish Population Estimates from Administrative Data Sources 2023 (IPEADS) is a Frontier Series output that estimates the usually resident population of Ireland in April 2023.It is the fourth such iteration of IPEADS and uses pseudonymised administrative data from public sector bodies to derive the Administrative Population in Ireland. This release includes breakdowns by several variables including sex, age, nationality, and economic status over four levels of geography - State, Local Authority, Local Electoral Area, and Electoral Division.
The quality of statistics on the Administrative Population depends on the quality, relevance and availability of administrative data to the CSO. Individual records on administrative data sets were not manually verified or corrected.
The IPEADS process uses pseudonymised data based on Protected Identifier Keys. For IPEADS, all identifying personal information is removed from administrative data used during the statistical process. This includes the Personal Public Service Number (PPSN), which is used to access social welfare, taxation, and other public services. When the PPSN is removed, the CSO generates a pseudonymised Protected Identifier Key (PIK) to replace it. The PIK is unique and non-identifiable and is only used by the CSO.
The PIK allows the CSO to link datasets for statistical purposes while protecting individual confidentiality. All linked records are pseudonymised, and results are published only as statistical aggregates that cannot identify individuals.
The matching exercise described in step 2 of the Geocoding and Statistical Geography Assignment phase of the IPEADS methodology uses datasets that result from a geocoding exercise performed by the CSO's Administrative Data Centre (ADC) on data containing personal identifiers. This exercise is performed securely by ADC staff as datasets contain personal identifiers. Strict access control is applied to these datasets and the IPEADS analysis is performed on a pseudonymised version of the dataset. At no point do IPEADS project staff have access to data containing personal identifiers.
The linkage and analysis were undertaken by the Central Statistics Office (CSO) for statistical purposes in line with the Statistics Act, 1993 and the CSO Data Protocol. More information on transparency can be found on the CSO website.
The CSO is committed to broadening the range of high-quality information it provides on social and economic change. The growing volume and complexity of secondary data presents both challenges and opportunities for national statistical institutes. Integrating secondary data sources across public service bodies, while complying with statistical and data protection legislation, enables new analyses that support evidence-based decision-making and accountability. A coordinated approach to data integration improves efficiency, reduces duplication, and lowers costs.
The CSO has a formal role in coordinating the integration of statistical and administrative data across public service bodies that together make up the Irish Statistical System (ISS). This integration is supported by the National Data Infrastructure which links data across administrative systems using unique identifiers for individuals, businesses, and locations. The CSO links pseudonymised datasets using only variables that are relevant to the specific statistical purpose. Data integration, supported by the collection of identifiers such as PPSNs and Eircodes, is central to the ISS’s goal of strengthening analytical capacity.
The NDI is essential to the creation of IPEADS. It enables the integration and standardisation of secondary data sources required to derive the Administrative Population. Data protection is a core principle of the CSO and is central to the development of the NDI. As well as the strict legal protections set out in the Statistics Act, 1993, and other existing regulations, we are committed to ensuring compliance with all data protection requirements. These include the Data Sharing and Governance Act (2019) and the General Data Protection Regulation (GDPR, EU 2016/679).
Administrative datasets were selected based on the following key criteria:
These criteria ensured that selected datasets could be reliably integrated to identify individuals who were usually resident in Ireland as of April 2023.
Individuals appearing in multiple datasets are linked using a pseudonymised version of the PPSN (the PIK), ensuring that each person is counted only once in the population estimate.
Children are identified in IPEADS using the following administrative sources:
Child Benefit (CB)
Contains information on benefit payments to parents or guardians for eligible children. Supplied annually by the Department of Social Protection. The Central Records System (CRS) is used to identify infants born in the year prior to the reference date who are not yet in receipt of Child Benefit.
Primary Online Database (POD)
Contains enrolment data for each student in recognised primary schools. Supplied annually by the Department of Education.
Post-Primary Online Database (P-POD)
Contains enrolment and school-level data for post-primary students. Supplied annually by the Department of Education.
Primary Care Reimbursement Service (PCRS – GMS)
Records payments made to healthcare providers for services under public health schemes. Managed by the Health Service Executive (HSE). Also includes data from the National Medical Card Unit (NMCU). Supplied annually by the HSE.
Students are identified in IPEADS using the following administrative sources:
Higher Education Authority (HEA)
Contains annual data on enrolments and graduations from publicly funded universities and institutes of technology. Supplied annually by the HEA.
Programme Learner Support System (PLSS)
Manages learner records and course enrolments in the further education and training sector. Supplied annually by SOLAS (Further Education and Training Authority).
Quality and Qualifications Ireland (QQI)
Provides data on qualifications awarded in further and higher education. Supplied annually by QQI.
Student Universal Support Ireland (SUSI)
Contains data on funding for eligible students in full-time higher and further education. Supplied annually by SUSI.
Individuals in this group are identified using the following administrative sources:
DSP Payments (DSP)
Contains monthly data on welfare payments, including state pensions, unemployment benefits, and adult child benefit recipients. Drawn from the Business Object Model implementation (BOMi) and Integrated Short-Term Payments System (ISTS). Supplied monthly by the Department of Social Protection.
PAYE Modernisation (PMOD)
Contains information on payslip submissions for individuals in employment and recipients of occupational pensions. Supplied monthly by the Revenue Commissioners. Coverage begins in 2019.
Self-employed individuals are identified using the following administrative source:
Form 11 Income Tax Returns (ITForm11)
Contains annual income tax return data for self-employed individuals. Supplied by Revenue. Due to the nature of self-assessment, full data coverage for a given year is typically available after three years, although most records are accessible approximately 14 months after the reference year.
The matching exercise described in step 2 of the Geocoding and Statistical Geography Assignment phase of the IPEADS methodology uses data that results from a geocoding exercise performed by the CSOs Administrative Data Centre (ADC). This exercise is performed securely by ADC staff outside the IPEADS process. IPEADS analysis is performed on a pseudonymised version of the dataset.
Local Property Tax (LPT)
The LPT file contains one record - the most recent LPT return - for each of the properties in the State. Local property tax returns are used to determine location (among other sources). Data is supplied by the Revenue Commissioner on an annual basis.
Central Records System (CRS)
The Central Records System (CRS) is a legacy system within the Department of Social Protection (DSP) which holds data on their customers on different systems within DSP. Data on a person’s address from the CRS is used in the geocoding exercise.
Department of Social Protection (DSP)
As described in the previous section, monthly datasets are supplied by the Department of Social Protection (DSP). Data on a person’s address from the DSP is used in the geocoding exercise.
Residential Tenancies Board (RTB)
The Residential Tenancies Board (RTB) was set up under the Residential Tenancies Act 2004. One of the RTB's main functions is to maintain a register of private residential tenancies, tenancies of approved housing bodies and student specific accommodation tenancies. Data on a person’s address from this RTB register is used in the geocoding exercise. Data is supplied by the RTB on a quarterly basis.
Housing Assistance Payment (HAP)
The Housing Assistance Payment (HAP) is a social housing support for people who have a long-term housing need. HAP is provided by a person’s local authority. Data on a person’s address from the HAP is used in the geocoding exercise.
Health Service Executive (COVAX: National COVID-19 Immunisation System)
The COVAX system is an electronic dataset which records all COVID-19 vaccinations for residents in the State. The COVAX vaccination data is only used in the geocoding exercise.
COVAX access is under Section 11 of the Statistics Act, 1993. The CSO’s use of COVAX data for official statistics is fully governed by CSO Data Protection protocols. The CSO’s access to sensitive and confidential health records is also underpinned by the written permission of the Minister for Health and provided under Section 30 of the Statistics Act, 1993 – ‘Use of Records of Public Authorities for Statistical Purposes’. This permission has been duly granted by the Minister.
Pandemic Unemployment Payments (PUP)
The COVID-19 Pandemic Unemployment Payment was a social welfare payment for employees and self-employed people who lost all their employment due to the COVID-19 public health emergency. Data on a person’s address from the PUP is used in the geocoding exercise.
Educational Datasets
Address data from educational datasets also feed into the geocoding exercise. These datasets include:
Data on a person’s address from the HEA, POD, P-POD and SUSI is used in the geocoding exercise.
Note: some individuals that may be administratively active may not live in the State, for example professionals commuting to work from Northern Ireland or individuals living abroad and receiving a state pension. Persons are excluded from the population count where indicators for usually resident outside Ireland are available from the administrative data sources listed above.
Data on sex and date of birth are sourced from the Central Records System (CRS), maintained by the Department of Social Protection (DSP).
As outlined in the Population Estimates chapter, data on nationality is derived from information collected by the DSP. For many individuals this data may have been collected several years ago and in some cases, people may no longer identify with the nationality recorded here. In particular, many people have become Irish citizens by naturalisation in the last 10 years or so. This more recent status may not be reflected in these statistics and may partly explain why the figures in this report differ from those reported elsewhere such as in the Population and Migration Estimates.
Nationality is classified using country codes (ISO 3166) and presented as follows;
Determining a person's principal economic status (PES) from administrative data is complex. In IPEADS, economic status is generally assigned based on the dataset in which the person is active around the reference period. For example, individuals with consistent monthly activity in PMOD are classified as ‘at work’.
If a person appears in multiple datasets during the reference period, a classification hierarchy is applied. For example, a university student who also works is assigned a status of ‘Student or pupil’.
Individuals in receipt of unemployment payments from the DSP during the reference period are assigned an economic status of ‘Unemployed’.
Note: Official labour force and unemployment estimates are produced from the Labour Force Survey (LFS), which relies on respondents’ self-reported status. The LFS follows the International Labour Organisation (ILO) definitions, using a structured set of survey questions. In contrast, IPEADS infers status from administrative activity. These methodological differences mean that estimates from IPEADS and the LFS are not directly comparable.
Economic sectors are classified using NACE Rev. 2 (2008), the EU’s standard framework for the statistical classification of economic activities. NACE groups individuals and organisations by their primary business activity. NACE codes are assigned to individuals classified as ‘At work’ using data from the PAYE Modernisation (PMOD) dataset or Form 11 Income Tax Returns (ITForm11) for the self-employed.
Data sources were chosen based on their capacity to meet the following criteria:
The contributing administrative data sources vary in how well they meet these criteria. The administrative data landscape continues to evolve, and the CSO will regularly review the quality and availability of both current and emerging sources.
A key challenge in deriving an administrative population count is the timing of data availability to the CSO. This constraint was a key factor in selecting the reference date (April 2023) for the population estimates.
Minimising the time lag between the reference date and publication improves the value of the estimates. “Real-time” datasets, such as PMOD and DSP Payments, are available within weeks, while others may have a time lag of up to 14 months. The April 2023 reference date was selected to optimise the use of the most timely data available. Future methodological changes will depend on evolving access to and timeliness of administrative data sources.
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