Table 1

Number of included studies, host RCTs and hypothetical RCTs categorised according to the new recruitment study types (A to D)

CategoryRecruitment study designRecruitment studies
(n=39)
Real host RCTs
(n=68)
Hypothetical host RCTs
(n=13)
ARCTs of interventions to optimise recruitment nested within one or more host RCTs11NA
BProspectively designed, non-randomised studies of interventions to optimise recruitment to one or more host RCTs33NA
CStudies describing recruitment experiences involving one or more host RCTs2464*NA
DStudies to consider recruitment within proposed hypothetical RCTs (commonly known as community consultations)11NA13†
  • *The 24 recruitment studies reported data from 64 real host RCTs, that is, a number of recruitment studies reported data from more than one real host RCT.

  • †The 11 recruitment studies reported data from 13 hypothetical studies, that is, two recruitment studies reported data from more than one hypothetical host RCT.

  • NA, not applicable—category does not apply to type of host RCT; RCT, randomised controlled trial.