This publication is categorised as a CSO Frontier Series Output. 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 the Background and Methodology section.
The results presented in this publication are based on a number of data sources:
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 [1] .
All data sources are pseudonymised prior to linking. The Personal Public Service Number (PPSN) is a unique number that enables individuals to access social welfare benefits, personal taxation and other public services in Ireland. The CSO removes the PPSN and replaces it with a Protected Identifier Key (PIK). The PIK is an encrypted and randomised number used by the CSO to enable linking of records across data sources and over time, while at the same time preserving privacy.
All results are in the form of statistical aggregates which do not identify any individuals.
The PIR is an 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 pseudonymised versions of administrative data holdings held by the Revenue Commissioners and Department of Social Protection. The PIR provides a near complete picture on individual level income, for a calendar year.
The RPPI dataset covers all market purchases of houses and apartments by households, both cash and mortgage-based transactions. Non-market transactions (e.g. family transfers) and non-household purchases (e.g. purchases by private companies or institutions) are specifically excluded from the RPPI index and this analysis. Also excluded are self-builds (i.e. where the land is purchased separately) and purchases of partially built dwellings. The main RPPI dataset is created from these administrative holdings – Stamp Duty returns, Building Energy Ratings (BER), the Geodirectory and the Pobal Deprivation Index [2].
The participant section of the Stamp Duty form provides information on individuals purchasing a property. For this analysis, the PPSN is extracted and also the address string provided. The PPSN is converted to a PIK and the address string is utilised to extract a broad geographic location (county or country if not in Ireland).
The Central Credit Register is a database of loans (of €500 or more), which includes information on consumer loans such as credit cards, mortgages, personal loans and overdrafts.
There are two types of buyer defined:
Gross income is defined as the sum of these three items in the year before the filing or execution of the Stamp Duty return:
Gross income for a sole transaction is the sum of the three items above for the purchaser. For a joint transaction, gross income is the sum of the three items above for all purchasers on the Stamp Duty return.
The CCR was linked to the property transaction dataset, through utilising a PIK which is created through deterministic matching techniques when creating the statistical analysis version of the CCR. A second challenge exists when linking the datasets in that there was no direct way to identify if the mortgage in question on the CCR relates to the property transaction on the Stamp Duty return dataset.
Therefore, the following methodology was adopted to identify whether a transaction involved a mortgage or not.
Statistics are produced in relation to the year a property transaction was filed with the Revenue Commissioners and the year the property transaction was executed. The ages of the people involved in the transactions are based on the year and month of when the transaction was filed or executed.
Gross income data, (defined above), relates to the calendar year before the Stamp Duty transaction was filed or executed. For example, for a Stamp Duty transaction filed or executed in 2016, the gross income used is for the reference year 2015. Therefore, transactions in year t use income data for year t-1. This was done because there was not enough information for 2021 incomes, (particularly for the self-employed), when this report was compiled.
If no Gross Income information is available in the calender year prior, gross income is set to missing.
The target population relates to all (participants) individuals who are involved in the RPPI’s definition of market-based household purchases over the period.
The actual population covered was smaller than the target population because of two main types of missing data – unique identifiers and demographic/income information.
When unique identifiers are absent, it may not be possible to assign a PIK.
When a PIK is not assigned, then income variables and demographic characteristics, (such as age) can’t be assigned to records. This means income characteristics can also not be assigned. In some cases, even where a PIK is assigned, it is still possible for income to be missing. Reasons for this can include that the person could:
For all these reasons above, the covered population is less than the target population.
Note that individuals without a PIK are assumed not to have a mortgage in the statistics or who couldn't be match to an in-scope mortgage on the CCR.
Between 2010 and 2019, 95% of individuals who bought a property were assigned a PIK. This varied from a low of 89.7% in 2010 to a high of over 99.9% in 2021. This variation also occurred across regions. Therefore, care should be taken when examining statistics in certain years, but also with certain lower level breakdowns.
In order to have a consistent income definition over a longer time series, income statistics are only produced from 2012 onwards.
Please note the following limitations of the analysis in this publication.
This report includes statistics based on counts from the stamp duty participant database of properties purchased and the number of individuals who purchased a property.
Statistics published on income, loan amount and prices have values rounded to the nearest hundred. Statistics published on counts have been rounded to the nearest ten.
Also, all count figures are rounded independently and therefore totals are more accurate than the sum of rounded sub-items. (Adding up the sum of rounded sub-items will give a different figure than the total for a category.)
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