Frequently, in experiments done before "double blind" and "control group" became the standard, we had results where something for which we were "struggling to f

Frequently, in experiments done before "double blind" and "control group" became the standard, we had results where something for which we were "struggling to find a reason" to be important, actually turned out to be important. In a properly done experiment we would not need to have a conversation in which lay people guess what else might have affected the results.