Randomized clinical trials adhere more closely to pre-agreed-on protocols than almost any
other type of experiment; yet we can tighten up their analysis if we desire. If we convert the
analysis into a randomization analysis—where the one set of data is analyzed many times—
once as though each acceptable assignment has been employed, we can eliminate any
dependence of the analysis on statistical or probabilistic assumptions. To do this effectively
when many assignments could be acceptable, we can go to double randomization, in which …