Table 1

‚ÄÉComparison of randomized controlled trials (RCTs) and statistical process control (SPC) for analysing dramatic improvements

Evaluation chracteristicsRCTSPC
Show treatment effect not due to chance (statistical power, tests of significance)Large sample sizeMuch greater statistical power to exclude chance as an explanation in the sequential context
To control for confounding factorsRandomizationPrior experience (everyone died regardless)
CausationExperimental change is causalPlausible process change which can be replicated with similar results
Speed of answerTypically in years for a large trialFor a large change the results can be demonstrated for one patient
EthicsWould you volunteer for such a trialNo one foregoes the new treatment
Use of knowledge from prior experience of outcomeNot usedUses knowledge of prior experience