Outside of randomized experiments, association does not imply causation, and yet there is nothing defective about our knowledge that smoking causes lung cancer,

Outside of randomized experiments, association does not imply causation, and yet there is nothing defective about our knowledge that smoking causes lung cancer,

An observational study is an empiric investigation of effects caused by treatments when randomized experimentation is unethical or infeasible. Observational stu

One of the pathways by which the scientific community confirms the validity of a new scientific discovery is by repeating the research that produced it. When a

This User’s Guide is a resource for investigators and stakeholders who develop and review observational comparative effectiveness research protocols. It expla