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PLoS One. 2014 May 29;9(5):e97886. doi: 10.1371/journal.pone.0097886. eCollection 2014.

Sharing individual participant data from clinical trials: an opinion survey regarding the establishment of a central repository.

Author information

North West Hub for Trials Methodology Research, Department of Biostatistics, University of Liverpool, Liverpool, England.
Centre for Statistics in Medicine, University of Oxford, Oxford, England.
All-Ireland Hub for Trials Methodology Research, Queen's University, Belfast, Ireland.
School of Health and Population Sciences, University of Birmingham, Birmingham, England.



Calls have been made for increased access to individual participant data (IPD) from clinical trials, to ensure that complete evidence is available. However, despite the obvious benefits, progress towards this is frustratingly slow. In the meantime, many systematic reviews have already collected IPD from clinical trials. We propose that a central repository for these IPD should be established to ensure that these datasets are safeguarded and made available for use by others, building on the strengths and advantages of the collaborative groups that have been brought together in developing the datasets.


Evaluate the level of support, and identify major issues, for establishing a central repository of IPD.


On-line survey with email reminders.


71 reviewers affiliated with the Cochrane Collaboration's IPD Meta-analysis Methods Group were invited to participate.


30 (42%) invitees responded: 28 (93%) had been involved in an IPD review and 24 (80%) had been involved in a randomised trial. 25 (83%) agreed that a central repository was a good idea and 25 (83%) agreed that they would provide their IPD for central storage. Several benefits of a central repository were noted: safeguarding and standardisation of data, increased efficiency of IPD meta-analyses, knowledge advancement, and facilitating future clinical, and methodological research. The main concerns were gaining permission from trial data owners, uncertainty about the purpose of the repository, potential resource implications, and increased workload for IPD reviewers. Restricted access requiring approval, data security, anonymisation of data, and oversight committees were highlighted as issues under governance of the repository.


There is support in this community of IPD reviewers, many of whom are also involved in clinical trials, for storing IPD in a central repository. Results from this survey are informing further work on developing a repository of IPD which is currently underway by our group.

[Indexed for MEDLINE]
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