Kudos to @ResearchProcess’s for finding and tweeting this: https://twitter.com/ResearchProcess/status/384527302106693634
Archive for September, 2013
The second attitude towards effectiveness is an agnostic one; such a clinician considers previous real world experience more relevant than efficacy figures when it comes to assessing effectiveness. Randomized Controlled Trial (RCT) results are not dismissed, but are discounted nonetheless at a very high rate. To the agnostic reading about the efficacy of an intervention in an RCT only implies that both success and failure are possible outcomes but the reported figures are not relevant. If the outcomes in real world patients rein supreme, then the trial results should be quantified in such a way as to correspond to such an experience. An extreme version of agnosticism will mathematically translate such an assessment to have the minimum possible influence, or equivalently the least number of “additional” patients that should be added to the real world record: one success and one failure “pseudocase”.
The believer’s attitude is one of unconditional trust to the results of the randomized clinical trial (RCT). The latter, not only provides “unbiased” estimates of the relative efficacy of two more therapies, but also furnishes numerical estimates of the absolute efficacy that translate more or less into the outcomes of real world clinical practice. The believer will thus views the results obtained in the clinic as interchangeable with the ones observed in the RCT, so that the mathematically consistent way to jointly examine them is to simply add together the corresponding successes and failures. This approach will work just fine if the underlying premise of equivalency between effectiveness and efficacy is true, yet it will backfire otherwise.
I will continue this series of posts regarding the appraisal of efficacy (“how well a therapeutic intervention worked in a randomized experiment”) and its translation to statements about effectiveness (“how well the intervention worked in the real world”), by considering the attitudes that one adopt towards these issues. The aim is to develop a sophisticated approach, or rather a vantage point that one would almost always want to adopt when considering the implications of having data about the efficacy (results of a trial) and effectiveness (success rate in real world practice). However the vantage point will only become evident by considering a basic set of attitudes, which are described here: (more…)