Background: Inductive reasoning relies on an infinite regress without sufficient factual
basis and verification is at any time vulnerable to single contrary observation. Thus, appraisal based
on inductive verification, as applied in current clinical trial appraisal scales, checklists or grading
systems, cannot prove or justify trial validity.
Discussion: Trial appraisal based on deductive falsification can identify invalid trials and give evidence
for the recommendation to exclude these from clinical decision-making. Such appraisal remains
agnostic towards corroborated trials that pass all appraisal criteria. The results of corroborated
trials cannot be considered more robust than falsified trials since nothing within a particular set of
complied trial criteria can give certainty for trial compliance with any other appraisal criterion in future.
A corroborated trial may or may not reflect therapeutic truth and may thus be the basis for clinical
guidance, pending results of any future trial re-appraisal.
Conclusion: Trial grading following appraisal based on deductive falsification should be binary (0 =
Invalid or 1 = Unclear) and single component scores should be multiplied. Appraisal criteria for the
judgment of trial characteristics require a clear rationale, quantification of such rationale and empirical
evidence concerning the effect of trial characteristics on trial results.