Addition of a diary (ID RET5)
Evidence Summary
What is it?
As opposed to the usual follow-up, participants receive a diary where they can record their experience.
Does it work?
Addition of a diary to usual follow-up probably reduces retention slightly.
How big is the effect?
An decrease of -3% (95% confidence interval = -4% to 2%).
How certain are we?
GRADE Moderate certainty.
Recommendation
We recommend that trialists add a diary to usual follow-up in the context of an intervention evaluation.
How can I use this straight away?
See Resource bundle below for details on how to add a diary to usual follow-up.
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 adding a diary to usual follow-up. The chart below shows the impact of an absolute decrease of -3% (95% CI = -2% to -4%). Retention is now 62%, which means our best estimate is that you would now be 18 responses short.
Cumulative Meta-Analysis*
Resource Bundle
How to Cite
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 small effect size and Moderate 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.
