Instead of a face-to-face meeting, participants are given information and consent is obtained over the telephone.
Providing information over the telephone may have little or no effect on recruitment.
A decrease of -7% (95% confidence interval = -18% to 5%).
GRADE Low certainty.
We recommend that trialists provide participant information over the telephone in the context of an intervention evaluation.
See Resource bundle below for details on how to provide participant information over telephone.
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 providing participant information over the telephone. The chart below shows the impact of an absolute decrease of -7% (95% CI = -18% to 5%). Recruitment is now 23%, which means our best estimate is that 130 people would now need to be approached to recruit 30 of them.