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Table 2 Details of the assessment of the internal pilots

From: A review of current practice in the design and assessment of internal pilots in UK NIHR clinical trials

  Frequency (%)
Design followed? (Yes/No)a
 Yes 49 (91%)
 No 5 (9%)
  Extended due to poor recruitment 2 (40%)
  Internal pilot delayed 3 (60%)
Committees involved in reviewb
 IDSMC only 3 (6%)
 TSC only 17 (35%)
 IDSMC, TSC 23 (47%)
 IDSMC, TSC, TMG 2 (4%)
 TSC, sponsor 3 (6%)
Continuation to main trial? (Yes/No)
 Yes, met criteria 33 (58%)
 Yes, did not meet criteria 14 (25%)
  Underwent a second reviewc 5 (36%)
  Continued with close monitoring 3 (21%)
  Recovery plan put in place 3 (21%)
  No reported actions taken 4 (29%)
 Yes, unclear whether criteria met 9 (16%)
 Decision on hold 1 (2%)
 No 0 (0%)
Number of planned pilot sites given?d (Yes/No)
 Yes 44 (79%)
 No 12 (21%)
 If yes, specifically named?
Yes 16 (36%)
No 28 (64%)
Number of planned pilot sites
 Median 6 (5, 10)
(interquartile range (IQR))
 Min, Max 2, 80
Number of planned sites for full trialf
 Median (IQR) 20 (13, 30)
 Min Max 3, 300
Adherence to plan regarding number of pilot sites?e (Yes/No)
 Yes 28 (72%)
 No 10 (26%)
  Opened further sites 6 (60%)
  Opened fewer sites 4 (40%)
 Missing 6
  1. aDesign not given in the protocol/proposal for 1 trial; unclear from the available information for 2 trials
  2. bNot given for 8 trials
  3. cSecond review involved revised recruitment targets; 1 trial underwent close monitoring alongside second review
  4. dNot applicable for 1 trial – no sites since recruitment takes place online
  5. eNumber of planned pilot sites not given for 12 trials
  6. fIncluding pilot sites; not given for 2 trials
  7. IDSMC Independent Data and Safety Monitoring Committee, TSC Trials Steering Committee, TMG Trial Management Group