Enhanced recruitment package with more contact by African Americans

An enhanced recruitment package with more contact may make little or no difference in recruitment.


The absolute increase is 0% (95% CI = -1% to 0%)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 an enhanced recruitment package with more contact by African Americans

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 enhancement
No enhancement

Now imagine recruiting using the enhanced recruitment package with more contact. The chart below shows the impact of an absolute increase of 0% (95% CI =-1% to 0%)1. Recruitment is still 30%, which means our best estimate is still that 100 people would need to be approached to recruit 30 of them.

With enhancement
With enhancement
By using enhanced recruitment including more contact, our best estimate is that you will need to approach the same number of people as without the enhancement.

Where has enhanced recruitment including more contact by African Americans been tested?


Including more telephone calls along with other enhancements such as an improved recruitment letter


No extra contact and standard recruitment letter and other techniques


1 study including a total of 6376 participants

Study 1: Ford 2004

African American men aged 55 to 74 eligible for a prostate, lung and colorectal cancer screening trial.

Trial intervention?
Unclear but recruitment is to cancer screening trials.

Study location?
Community, USA.

What difference?
2.5% of participants randomised to enhanced recruitment with more contact were recruited; 2.9% of participants randomised to not get enhanced recruitment were recruited

Read more about this study here.

What we still don’t know about enhanced recruitment including more contact by African Americans

  • The GRADE assessment is low for this intervention because the risk of bias was unclear 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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