Participant information leaflet (PIL) development #2: with user feedback

Optimising the PIL through using user feedback probably makes little or no difference to recruitment.


The absolute increase is 0% (95% CI = 0% to 1%)1

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

MODERATE 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 user feedback on PILs

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 below).

Standard PIL process
With standard PIL process

Now imagine using a participant information leaflet developed using feedback. The chart below shows the impact of an absolute increase of 0% (95% CI = -2% to 2%)1. Recruitment is still 30%, which means our best estimate is that 100 people would still need to be approached to recruit 30 of them.

With PIL user feedback
With PIL user feedback
By using PIL user feedback, our best estimate is that you will need to approach the same number of participants as with a standard PIL process.

Where have brief participant information leaflets (PIL) been tested?


PIL with user feedback


Standard PIL process


2 studies including a total of 16763 participants

Study 1: Cockayne 2017

Patients eligible for the REFORM study (over 64 years, routine podiatry appointment in past 6 months) and offered an appointment at NHS podiatry clinics across 5 centres.

Trial intervention?
An orthosis.

Study location?
Community NHS clinics, UK.

What difference?
3.0% of those receiving the PIL with user feedback were recruited; 2.7% of those receiving the standard PIL were recruited.

Read more about this study here.

Study 2: Chen 2011

Participants were eligible for 3 host trials, but unclear what the trials were.

Trial intervention?

Study location?
Unclear but probably secondary, UK.

What difference?
6.1% of those receiving the PIL with user-feedback were recruited to a pre-randomisation phase; 5.6% of those receiving the standard PIL were recruited to the pre-randommisation phase.

Read more about this study here.

What we still don’t know about PILs with user feedback

  • The information we have is based on a two trials, one of which (Chen 2011) us actually recruitment to a pre-randomisation phase so has pulled down the GRADE rating to moderate because of indirectness. Ideally we need to test this intervention in more trials.
  • Both trials were done in the UK; evaluations outside the UK would be welcome.
  • Please get in touch (email if you would like to do an evaluation because we can help with text for ethics etc.

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