Dichotomization

Great discussion. It is really too bad that Guyatt writes on statistical topics but does not have the necessary statistical background for doing so. The simplest error of logic I can think of that fans of responder analysis make is that thresholds for interpretation of results should lead to thresholds and associated dichotomization of the raw response variable. Were that the case, olympic track coaches would not need stopwatches and cars would not need speedometers. Another simply stated problem with responder analysis is that a treatment may move those above a threshold to be far above the threshold, but the proportion “responding” would miss that.