One of the first RCT: we should never forget that reducing uncertainty is feared at first look by physicians and patients.

http://gallica.bnf.fr/ark:/12148/bpt6k103986t/f10.image

About bloodletting and mortality rate in pneumonia

A brief history of RCT

http://odin.mdacc.tmc.edu/~jjlee/clinical_trials2008/Greenfield,%20historical%20highlights%20of%20randomized%20controlled%20trial.pdf

This fear of a lesser uncertainty has a signification about the preference of our brain. When we have strong projects we seek for a lesser uncertainty and when we haven't we tolerate or prefer a higher uncertainty.