Developing principles for sharing information about potential trial intervention benefits and harms with patients: report of a modified Delphi survey

Martina Svobodova, Nina Jacob, Kerri Hood, Katie Gillies, Rachel Hale, Jennifer Bostock, Peter Bower, Adrian G. Edwards, Penelope Farthing, Sarah Rawlinson, Shaun Treweek, Jeremy Howick* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
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Background: The way information about potential harms of trial intervention is shared within participant information leaflets (PILs) varies widely and can cause subjective ‘nocebo’ harms. This study aimed to develop principles to improve the composition of information about potential trial intervention benefits and harms within PILs so that variability and avoidable harms are reduced.
Methods: We conducted a two-round modified online Delphi survey, followed by a consensus meeting. For the first round of the survey, 27 statements were developed based on previous research and relevant guidance from the UK, the USA and the World Health Organization. Participants included members from each of the following stakeholder groups: patient and public representatives, research ethics committee members, industry representatives, medico-legal experts, psychologists and trial managers. Each participant was asked to rate their degree of agreement or disagreement with each statement on a 9-point Likert scale. In the second round, participants were invited to reappraise their ratings after reviewing the results of the first round. Finally, two members from each stakeholder group participated in a meeting to confirm those statements for which there was agreement.
Results: Two hundred and fifty participants completed round 1, and 201 participants completed round 2. In round 1, consensus was reached for 16 statements. In round 2, consensus was reached for an additional three statements. The consensus meeting confirmed the survey results and consolidated the statements. This process resulted in seven principles: (1) all potential harms of a given intervention should be listed, (2) all potential harms should be separated into serious and less serious, (3) it must be made explicit that not all potential harms are known, (4) all potential benefits should be listed, (5) all potential benefits and harms need to be compared with what would happen if the participant did not take part in the trial, (6) suitable visual representations should be added where appropriate and (7) information regarding potential benefits and harms should not be presented apart by one or more pages.
Conclusions: Our modified Delphi process successfully generated seven principles that can and should be used to guide how information is conveyed to patients in information leaflets regarding potential trial benefits and harms.
Original languageEnglish
Article number863
Number of pages9
Issue number1
Early online date8 Oct 2022
Publication statusPublished - Dec 2022

Bibliographical note

Funding Information:
This study is funded by the Medical Research Council (MRA reference MR/V020706/1).

We are grateful to all of the participants for considering the study, for giving their time to participate and for sharing their views with us. We would like to extend special thanks to the Delphi Consensus meeting participants: John Grimes, Adele Battaglia, Gwyn Thomas, Fida Issa, Rebecca Webster, Peter Knapp, Bob Phillips, Karen Ma, Sarah Birch and Pam Shuttleworth.

Data Availability Statement

The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.


  • Clinical trials
  • Medical risk factors
  • Nocebo effect
  • Participant information leaflet
  • Risk communication


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