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Table 1 Details of the design of the internal pilots

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

  Frequency (%)
Data sources
 Commissioning briefs 28a (100%)
 Project descriptions 41 (72%)
 Summary of changes from first stage/feedback about full application 41 (72%)
 Monitoring notes 56 (98%)
 Progress report history 56 (98%)
 Protocols (current version available online) 57 (100%)
 Protocols (any previous versions available online) 37 (65%)
Where was the internal pilot first proposed?
  Funder-led Researcher-led
 Commissioning brief 8 (29%) N/A
 Outline 6 (27%) 14 (64%)
 Outline feedback 6b (27%) 7c (32%)
 Full application 0 (0%) 0 (0%)
 Full application feedback 2 (9%) 1 (5%)
 Total 22d (100%) 22d (100%)
Trials with progression criteria specified in the latest available version of the protocol
 Yes 36 (63%)
 No 21 (37%)
 If yes, specified in previous available versions?
Yes 19 (86%)
No 3 (14%)
 Previous versions not available 14
Component(s) of progression criteriae
 Target number for recruitment within a specified period 54 (96%)
 In a specified number of sites?
Yes 4 (7%)
No 50 (93%)
 Retention/primary outcome ascertainment rate 16 (29%)
 Rate of treatment adherence 13 (23%)
 Rate of randomisation over time 11 (20%)
 Rate of randomisation by site?
Yes 8 (73%)
No 3 (27%)
 Number of sites recruiting 10 (18%)
 Consent rate 8 (14%)
 Number of sites opened 5 (9%)
 Proportion of eligible participants 3 (5%)
 Otherf 4 (7%)
  1. aDenominator 28 as only applicable for the 28 funder-led trials
  2. bThe outline feedback suggested amendments to an additional 6 internal pilots, 4 of which were initially proposed in the commissioning brief and 2 which were proposed in the outline
  3. cThe outline feedback suggested amendments to an additional 8 internal pilots, all of which were initially proposed in the outline
  4. d5 unknown for funder-led trials; 8 unknown for researcher-led trials; commissioning brief denominator = 28
  5. eCriteria was not specified for 1 internal pilot so denominator taken as 56
  6. fNumber of UK participants; number receiving rescue treatments; outcome assessments conducted according to protocol; number of sites that completed the intervention course