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Table 3 Main and supplementary results

From: The matching quality of experimental and control interventions in blinded pharmacological randomised clinical trials: a methodological systematic review

Paper Main results:
proportion of trials with inadequate matching based on the conclusion of the publications
Supplementary results: Proportion of trials with inadequate matching
based on high/low thresholdsa
  High threshold Low threshold
Hill and collegues, 1976 7 of 22 trials 6/22 trials 14/22 trials
Blumenthal and colleagues, 1974 5 of 6 trials 5/6 trialsb 5/6 trials
Walter and colleagues, 2005 1 of 1 trial 0/1 trial 1/1 trial
Fai and colleagues, 2011 0 of 1 trial 0/1 trial 1/1 trialc
Dupin-Spriet and colleagues, 1993 1 of 3 trials 0/3 trials 3/3 trials
Wen and colleagues, 2004 1 of 1 trial 1/1 trials 1/1 trials
Farr and colleagues, 1987 1 of 2 trials 0/2 trialsd 1/2 trialse
  1. aThe high thresholds are in most cases based on at least 75 % of assessors finding clear differences. The low thresholds are in most cases based on 25 % of assessors finding clear differences
  2. bTwo groups of assessors were involved. In one group (patient-simulated), only in one trial did 75 % or more of assessors find clear difference between experimental and control intervention. In the second group of assessors (experimenter-simulated), over 80 % of assessors found clear differences in five out of six experimental and control drugs
  3. cTaste was excluded from the study because “taste was not adjusted with bitter agent” though the experimental intervention most likely had a more bitter taste
  4. dBased on chance alone, 50 % of assessors would be expected to correctly guess intervention types. We defined high threshold to imply that at least 75 % of assessors randomized to the experimental intervention perceived being on the experimental intervention
  5. eSignificantly more than 50 % of assessors randomized to experimental group perceived to have received the experimental intervention