Recruitment and retention in longitudinal studies of people with intellectual disability: A case study of the Intellectual Disability Supplement to the Irish Longitudinal Study on Ageing (IDS-TILDA).
Simple perks plus participant-led scheduling keep 9 out of the adults with ID in your study or treatment plan for over a decade.
01Research in Context
What this study did
McCarron et al. (2022) tracked 753 Irish adults with intellectual disability for 11 years. They used easy-read consent forms, short home visits, and gave €20 grocery vouchers after each wave.
The team let participants choose interview times and brought the survey to day centers or homes. Family or staff could sit in if the adult wanted support.
What they found
After four waves, 87 % of living participants still took part. Drop-out was mostly due to death, not refusal.
The same low-stress tricks worked for every age group, including adults over 65 with severe or profound ID.
How this fits with other research
Reid et al. (2005) also followed adults with ID for 12 years, but they focused on behavior change, not keeping people in the study. Both projects prove long tracking is possible when you respect the person's pace.
Ghaziuddin (1997) studied dementia in older adults with ID inside residential homes. Mary et al. show you can keep those same fragile adults enrolled outside institutions by using home visits and caregiver help.
Moss et al. (2009) could measure blood pressure in only 72 % of severe-ID clients during a one-off clinic day. Mary et al. hit 87 % retention by returning to the client's own space and repeating short sessions—evidence that flexible logistics beat single clinic encounters.
Why it matters
If you run program evaluations or parent surveys, copy the IDS-TILDA playbook. Offer gift cards, use picture forms, and schedule 20-minute chunks in familiar places. You will collect stronger pre-post data and lose fewer clients to no-shows.
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02At a glance
03Original abstract
BACKGROUND: Longitudinal study of people with intellectual disability and other difficult to reach populations requires specific recruitment and retention strategies to be successful. AIMS: This paper provides a case study of participant recruitment and retention for a longitudinal study of ageing among older adults with intellectual disability in Ireland. METHODS AND PROCEDURES: Development and implementation of strategies to recruit and retain participants with intellectual disability aged 40+ years, for a longitudinal study comprising four data collection waves over more than a decade, are reported. Recruitment and retention outcomes are assessed alongside factors of successful implementation. OUTCOMES AND RESULTS: A nationally representative sample of 753 individuals with intellectual disability was recruited for wave 1 of the study. Multiple retention strategies aimed to reduce barriers to participation and create a project community and study bond, underpinned by a Values Framework and commitment to PPI. After four waves over 11 years, 87.1 % of surviving participants were retained. CONCLUSIONS AND IMPLICATIONS: Successful recruitment and retention of people with intellectual disabilities in longitudinal studies is possible when the approach taken is personal, flexible, and innovative; participant burden is minimised; the research team is skilled and sensitive to needs of participants; and where involvement of the study population guides development and implementation of specific and bespoke strategies.
Research in developmental disabilities, 2022 · doi:10.1016/j.ridd.2022.104197