Enclosing a questionnaire covering issues relevant to trial with the invitation
Enclosing a questionnaire covering issues relevant to trial with the invitation probably increases recruitment.
5%
The absolute increase is 5% (95% CI = 2% to 8%)1
MODERATE CERTAINTY in the evidence (but see 'What we don't know' below)
The practical impact of enclosing a questionnaire covering issues relevant to trial with invitation
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 (see chart below).
Now imagine enclosing a questionnaire with the invitation. The chart below shows the impact of an absolute increase of 5% (95% CI =2% to 8%)1. Recruitment is now 35%, which means our best estimate is that 86 people would need to be approached to recruit 30 of them.
Where has enclosing a questionnaire covering issues relevant to trial with the invitation been tested?
Intervention:
Comparison:
Scale:
Study 1: Kendrick 2001
Participants?
Families with children aged under 5 years, living in deprived areas.
Trial intervention?
Health visitor advice and low cost safety equipment.
Study location?
Primary care, UK.
What difference?
18% of participants randomised to receive a questionnaire were recruited; 13% of participants randomised to not get a questionnaire were recruited
What we still don’t know about enclosing a questionnaire covering issues relevant to trial with the invitation
- The GRADE assessment is still only moderate for this intervention because there is only a single evaluation. More evaluations in any type of trial are needed.
- Please get in touch (email info@trialforge.org) if you would like to do an evaluation because we can help with text for ethics etc.
