The Irish Longitudinal study on Ageing (TILDA)


Study number (SN): 0053-01 (Wave 1) 


Study number (SN): 0053-02 (Wave 2) 


Study number (SN): 0053-03 (Harmonized TILDA) 


Study number (SN): 0053-04 (Wave 3) 

TILDA logo small


Study number (SN): 0053-05 (Wave 4) 


Study number (SN): 0053-06 (Wave 5)


Study number (SN): 0074-00 - TILDA COVID-19 Study 2020



TILDA collects information on all aspects of health, economic and social circumstances from adults aged 50 years and over resident in Ireland. Waves of data collection take place every two years. TILDA provides a comprehensive and accurate picture of the characteristics, needs and contributions of older persons in Ireland to inform and support improvements in policy and practice; advancements in technology and innovation; tailored education and training through an enhanced ageing research infrastructure; harmonisation with leading international research to ensure adoption of best policy and practice and comparability of results. TILDA is necessary to act as the foundation on which we can plan appropriate health, medical, social and economic policies for our older adults.



  • Ageing
  • Cognitive processes
  • Economic conditions
  • Health
  • Health status
  • Income
  • Lifestyle and health
  • Mental health
  • Retirement
  • Social participation





A nationally representative sample of community-dwelling adults aged 50 years and over, resident in Ireland, were recruited at baseline (n=8,504).

Observation units

  • Individual
  • Families / Households

Temporal coverage

See individual waves for details

Time dimension

Follow-up to cross-sectional study (e.g. longitudinal); Cohort study

Geographical coverage

Country: Republic of Ireland

Methods of data collection

  • PAPI (Paper and Pencil Interviewing): Self-completion (distributed by post, email or other)
  • CAPI (Computer Aided Personal Interviewing)

Sampling procedures

An initial multi-stage sample of addresses was chosen by means of the RANSAM sampling procedure, which was developed by the Economic and Social Research Institute (ESRI) based on the Irish Geodirectory, a comprehensive listing/mapping of residential addresses in Ireland compiled by the Ordinance Survey Office.

Stage 1: RANSAM groups the residential addresses in the country into 3,155 first stage units or clusters. These clusters are townlands or aggregations of townlands and range in size from 500 to 1180 addresses. It was decided to select 640 of these clusters, with implicit proportionate stratification of clusters by socio-economic group (3 categories) and geography. Characteristics of the clusters can be inferred from the District Electoral Divisions of which they are a part, on the basis of the Small Area Population Statistics compiled by the Central Statistics Office. Stratification was achieved by pre-sorting all addresses in the country by socio-economic group (three equal groups on the basis of percentage of the population in the professional/managerial category) and within socio-economic group by RANSAM’s geographical “snake” pattern which orders clusters within county based on a north/south pattern which preserves contiguity. Clusters were selected randomly with a probability of selection proportional to the estimated number of persons aged 50 or over in each cluster.

Stage 2: This stage involved the selection of a probability sample of 50 addresses within each cluster (10 to be held in reserve). The combination of selection probabilities used at the two stages produces an equal probability (“epsem“) sample of addresses. All persons aged 50 or over in the selected households (and their spouses or partners of any age) were asked to participate. The addresses were partitioned into two groups: an initial sample list of 25,600 addresses (40 randomly selected from each of the 640 clusters) for immediate issue to the field force and 6,400 addresses (10 randomly selected from each of the 640 clusters) for retention as a reserve list. The reserve list would only be utilised later in the fieldwork process if it appeared unlikely that the target sample size would be achieved however this was not the case and the reserve list was not used.

As described, the sample design incorporates stratification, clustering and multi-stage selection. The design results in an equal probability sample of both households containing members of the target population and of persons in the target group. This means that the resulting sample is “epsem” and self-weighting, except for biases caused by non-random variations in response rates. Such biases were dealt with at analysis stage by means of calibration weights.


Response rate

The response rate is the proportion of selected households including an eligible participant from which an interview was successfully obtained. Interviewers were sent to all of the initially allocated 25,600 addresses. Of these, 22,321 were occupied residential addresses. At 11,819 addresses, contact was made and it was determined than no person aged 50 years or over was living at that address. At 9,818 addresses, it was determined that there was a resident person aged 50 years or over. At 684 addresses, either no contact was made or contact was made but it was impossible to determine whether there was anybody aged 50 years of over living at that address. Based on those households in which eligibility was determined, it is estimated that 9,818/(9,818+11,819) x 684 = 310.4 of the 684 households contained an eligible participant. The estimated number of selected eligible households is therefore 9,818 + 310.4 = 10,128.4. Successful interviews were obtained in 6,279 households, leading to a response rate of 62.0%.

See individual waves for further details.


Copyright Statement

Copyright and all other intellectual property rights relating to the data, and any documentation concerning the collection of TILDA data, are vested in The Irish Longitudinal Study on Ageing and Trinity College Dublin.




Data (available through ISSDA application process)

See individual waves for details


Documentation (available for download)

See individual waves for details

File name

File format/s

(preferably PDF)

Contents of file



Detailed description of data and collection methods



The Design of the Irish Longitudinal Study on Ageing



Fifty Plus in Ireland 2011: First results from the Irish Longitudinal Study on Ageing (TILDA)



THE OVER 50s IN A CHANGING IRELAND: Economic Circumstances, Health and Well-Being

0053-04 TILDA Wave 3 Key Findings Report


HEALTH AND WELLBEING:Active Aging for Older Adults in Ireland. Evidence from The Irish Longitudinal Study on Ageing

0053-00 TILDA Cohort Maintenance Strategies


Cohort Maintenance Strategies used by The Irish Longitudinal Study on Ageing (TILDA)





For more documentation including documentation for each individual wave of the TILDA study, please see the following page: 



Cronin H, O'Regan C, Kearney P, Finucane C, Kenny RA. 2013. Health and Ageing: Development of the TILDA health assessment. Journal of the American Geriatrics Society. 61(s2): S269-278.

Kearney PM, Cronin H, O'Regan C, Kamiya Y, Savva GM, Whelan B, Kenny RA. 2011. Cohort Profile: the Irish Longitudinal Study on Ageing. International Journal of Epidemiology. 40(4):877-84.

Whelan BJ and Savva GM. 2013. Design and Methodology of the TILDA Study. Journal of the American Geriatrics Society. 61(s2): S265-68. 


Register of Use

ISSDA maintains an opt-in register of projects using TILDA data in their research.  



Accessing the data

To access the data, please complete the ISSDA Data Request Form for Research Purposes, sign it, and send it to ISSDA by email.

For teaching purposes, please complete the ISSDA Data Request Form for Teaching Purposes, and follow the procedures, as above. Teaching requests are approved on a once-off module/workshop basis. Subsequent occurrences of the module/workshop require a new teaching request form.

Data will be disseminated on receipt of a fully completed, signed form. Incomplete or unsigned forms will be returned to the data requester for completion.


Any work based in whole or part on resources provided by the ISSDA, should  acknowledge: “The Irish Longitudinal study on Ageing (TILDA)" and also ISSDA, in the following way: “Accessed via the Irish Social Science Data Archive -”.

Citation requirement

The data and its creators shall be cited in all publications and presentations for which the data have been used. The bibliographic citation may be in the form suggested by the archive or in the form required by the publication.

Bibliographical citation

See individual Waves for suggested citations.


The user shall notify the Irish Social Science Data Archive of all publications where she or he has used the data.


If you have any queries relating to this dataset please read our FAQs 

Available also as a PDF TILDA - Frequently Asked Questions


For a list of Sports related datasets click here.


For a list of Health related datasets click here.



For all TILDA publications click here