Efficacy versus Effectiveness We underlined that efficacy and effectiveness describe two different types of information: efficacy is the demonstration that a new principle can theoretically work, which comes from studies under ideal controlled conditions; effectiveness is how the concept proven by efficacy studies works under real world conditions (RWC)., For demonstration of efficacy, one should select the optimal scenario for the proof of principle. It requires an experimental study design, with random allocation of treatments, to eliminate confounding bias and […]