Evidence Summary
What is it?
Instead of giving people the choice to opt-in a study, they are given the choice to opt-out.
Does it work?
Opt‐out consent may improve recruitment.
How big is the effect?
An increase of 19% (95% confidence interval = 3% to 35%).
How certain are we?
GRADE Low certainty.
Recommendation
We recommend that trialists consider using opt-out rather than opt-in consent.
How can I use this straight away?
See Resource bundle below for details on how to use opt-out consent.
Practical Impact
Imagine a trial that needs to recruit 30 participants and initial recruitment is 30% of those approached. This means you’d need to approach 100 people to recruit 30 of them (see chart).
Now imagine using opt-out rather than opt-in consent. The chart below shows the impact of an absolute increase of 19% (95% CI = 3% to 35%). Recruitment is now 49%, which means our best estimate is that 61 people would now need to be approached to recruit 30 of them.
Cumulative Meta-Analysis*
*Random effects model done using Comprehensive Meta-Analysis v4 (www.meta-analysis.com).
Differences >0% favour the intervention. The GRADE assessment is low because of the imprecision of a single study.
Resource Bundle
How to Cite
Citation: Treweek S, Bruhn H, Gardner H. Evidence pack– Recruitment: Opt-out rather than opt-in consent (REC10), 2023, https://www.trialforge.org/recruitment-sector/opt-out-rather-than-opt-in-consent-id-rec10
More Information
- This summary is from the Cochrane review of strategies to improve recruitment in randomised trials (https://doi.org/10.1002/14651858.MR000013.pub6).
- It was prepared with financial support from Evidence Synthesis Ireland.
- The ‘Does it work?’ statement is structured according to effect size and GRADE certainty as per GRADE Guidelines 26 (https://doi.org/10.1016/j.jclinepi.2019.10.014). The statement is for a large effect size and GRADE Low certainty.
- The recommendation statement is the consensus view of the authors of this summary based on the GRADE certainty and features of the trials contributing to the evidence.
- If you have any questions contact info@trialforge.org.
