Why do eligible interventions have to be implemented and evaluated in a minimum of three different sites?

The intervention must be implemented and evaluated in at least three distinct sites to allow assessment of replicability. We are interested in how generalizable the interventions are as well as how they might need to be tailored for different settings to be most effective. Our goal is to study intervention implementation in sites that, when compared to each other, provide unique administrative structures, target populations, geographic regions or patient care systems.

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I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.