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Recruitment at a church and other enhancements (ID REC11)

Evidence Summary

What is it?

Recruitment is organised either via telephone interviews, an enhanced mailed packet (one that is written by and includes the photograph of a prominent local community member) or during church-based project sessions.

Does it work?

Recruitment at a church and other enhancements may improve recruitment.

How big is the effect?

An increase of 1% (95% confidence interval = 0% to 2%).

How certain are we?

GRADE Low certainty.


We recommend that trialists consider recruitment at churches and using other enhanced recruitment methods.

How can I use this straight away?

See Resource bundle below for details on how to recruit at churches and implement other recruitment enhancements.

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 recruitment at church and other enhancements. The chart below shows the impact of an absolute increase of 1% (95% CI = 0% to 2%). Recruitment is now 31%, which means our best estimate is that 97 people would now need to be approached to recruit 30 of them.

Cumulative Meta-Analysis*

*Random effects model done using Comprehensive Meta-Analysis v4 ( 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: Recruitment at a church and other enhancements (REC11), 2023,

More Information

  1. This summary is from the Cochrane review of strategies to improve recruitment in randomised trials (
  2. It was prepared with financial support from Evidence Synthesis Ireland.
  3. The ‘Does it work?’ statement is structured according to effect size and GRADE certainty as per GRADE Guidelines 26 ( The statement is for trivial, small unimportant effect or no effect and GRADE Low certainty.
  4. 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.
  5. If you have any questions contact
v2.0 - 10/07/2023
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