Evidence Summary
What is it?
Alongside with the follow-up questionnaire, participants receive a voucher or some cash.
Does it work?
Monetary incentives may increase retention.
How big is the effect?
An increase of 7% (95% confidence interval = 4% to 11%).
How certain are we?
GRADE Low certainty.
Recommendation
We recommend that trialists consider using monetary incentives along with the reminder questionnaire.
How can I use this straight away?
See Resource bundle below for details on how to implement financial incentives.
Practical Impact
Imagine initial retention is 65% of those approached. You have a trial with 100 participants that needs responses from 80 to meet its statistical power calculations. Retention of 65% means that you will be 15 responses short (see chart below).
Now imagine using financial incentives. The chart below shows the impact of an absolute increase of 7% (95% CI = 4% to 11%). Retention is now 72%, which means our best estimate is that you would now only be 8 responses short.
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 imprecision.
Resource Bundle
How to Cite
Citation: Ostrovska B. Evidence pack– Retention: Financial incentives (RET11), 2023, https://www.trialforge.org/retention-sector/financial-incentives-id-ret11/.
More Information
- This summary is from the Cochrane review of strategies to improve retention in randomised trials (https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.MR000032.pub3/full).
- 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 moderate effect size and Low GRADE 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.
