Frequent telephone contact (ID RET9)
Evidence Summary
What is it?
Participants receive a phone call at baseline, after six months and at annual visits for three years after that as opposed to a call at baseline only.
Does it work?
Frequency of telephone contact may increase retention.
How big is the effect?
An increase of 6% (95% confidence interval = -5% to 17%).
How certain are we?
GRADE Low certainty.
Recommendation
We recommend that trialists consider keeping up regular phone contact with participants.
How can I use this straight away?
See Resource bundle below for details on how to implement frequent telephone contact.
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 frequent telephone contact. The chart below shows the impact of an absolute increase of 6% (95% CI = -5% to 17%). Retention is now 71%, which means our best estimate is that you would now only be 9 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 large 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.
