Table 4.
Examples of adequately detailed descriptions of partially clustered trial designs for published trial reports.
| Trial type |
|---|
| Individual randomisation with post-randomisation clustering |
| ‘The trial was a partially clustered, individually
randomised group treatment trial with a waitlist control
group. Participants were randomised to intervention or
control, and within the intervention group facilitators
administered a health promotion program to small groups of
8–12 participants’. Group-based treatment design: ‘The trial was a two-arm parallel, partially clustered, randomised, controlled trial. Participants were individually randomised to intervention or control, and intervention participants were subsequently clustered into groups for delivery of the counselling sessions in a group-based treatment design’. Facilitator effect design: ‘The trial is designed as a multi-centre, parallel group, individually randomised, controlled trial with partial clustering. Physiotherapists will deliver the intervention to participants individually, with each physiotherapist expected to treat an average of 7 participants’. |
| Individual randomisation within pre-existing clusters |
| ‘The trial was a randomised, blinded, controlled trial, with
partial clustering of infants from multiple births. All
infants were randomised
individually’. Re-randomisation design: ‘The trial is a pragmatic, partially clustered, two-arm parallel-group randomised controlled trial using re-randomisation’. |
| Cluster randomisation of pre-existing clusters |
| ‘The trial is a prospective, multi-centre, open-label, randomised trial. If inclusion criteria were met, one or both eyes of eligible participants were enrolled in the study and received the same treatment, hence this a partially clustered trial with cluster randomisation’. |
| Balanced randomisation within pre-existing clusters |
| ‘This was a phase 3, single centre, randomised, partially clustered, controlled trial involving patients scheduled for elective vascular surgery with either unilateral or bilateral inguinal incisions. In the case of bilateral incisions, the right incision was randomised to intervention or control, and the left incision received the alternate treatment’. |
Source: Adapted from real examples of partially clustered trial reports.