Providing participant information over the telephone rather than face-to-face

Providing participant information over the telephone rather than face-to-face may have little or no effect on recruitment.

-7%

The absolute effect is a reduction of 7% (95% CI = -18% to 5%)1

How confident are we in the evidence?  
What is GRADE?

LOW CERTAINTY in the evidence (but see 'What we don't know' below)


1 Treweek S, Pitkethly M, Cook J, Fraser C, Mitchell E, Sullivan F, Jackson C, Taskila TK, Gardner H. Strategies to improve recruitment to randomised trials. Cochrane Database of Systematic Reviews 2018, Issue 2.

The practical impact of providing participant information over the 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 (see chart below).

No information over telephone
No information over telephone

Now imagine providing participant information over the telephone. The chart below shows the impact of an absolute reduction of 7% (95% CI =-18% to 5%)1. Recruitment is now 23%, which means our best estimate is that 130 people would need to be approached to recruit 30 of them.

Providing information over telephone
Providing information over telephone
By providing participant information over the telephone as opposed to no telephone information, our best estimate is that you will need to approach 30 more participants.

Where has providing participant information over the telephone been tested?

Intervention:

Providing participant information over the telephone

Comparison:

Information provided face-to-face

Scale:

1 study including a total of 118 participants

Study 1: Foss 2016

Participants?
Women giving birth at 1 of 3 hospitals and eligible for a vaccination trial.

Trial intervention?
Neonatal Bacille Calmette-Guérin vaccine.

Study location?
Secondary care, Denmark.

What difference?
85% of participants randomised to receive telephone information were recruited; 92% of participants randomised to face-to-face information were recruited

Read more about this study here.

What we still don’t know about providing information over the telephone

  • The GRADE assessment is low for this intervention because of imprecision and 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.

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