Table 2

Summary of the realised design features of the included stepped-wedge cluster randomised trial. Values are numbers (percentages) unless stated otherwise

Full trial report
Number of steps*
 Two9 (28.1)
 Three or four8 (25.0)
 More than four14 (43.8)
 Not reported1 (3.1)
 Median (IQR)4.0 (2.0–6.0)
Number of clusters
 Less than 109 (28.1)
 10 or more22 (68.8)
 Not reported1 (3.1)
 Median (IQR)17.0 (8.0–38.0)
Total cluster size†
 Median (IQR)55.0 (24.0–326.0)
Number of clusters randomised per step
 Median (IQR)3.0 (1.0–8.0)
Number of measurement points‡
 Median (IQR)5.0 (3.0–7.5)
Study duration (months), median (IQR)16.0 (8.0–24.0)
Step duration (months), median (IQR)2.0 (1.0–4.0)
Design type§
 Cross-sectional5 (15.6)
 Cohort12 (37.5)
 Open cohort10 (31.3)
 Unclear5 (15.6)
Variations on design
 Transition periods1 (3.1)
 Extended pre-period or postperiod11 (34.4)
 Other6 (18.8)
  • *Steps are points at which clusters are randomised.

  • †For cohort studies this is the total number of observations made within the cluster, it includes the size of clusters in which there was lack of clarity of cluster size and cluster size per measurement period but for which a judgement was made.

  • ‡Measurement points are the number of separate periods or points in time in which outcome data are collected.

  • §Design type includes those for which there was lack of clarity but for which a judgement was made.