An observational study is an empirical investigation of the effects of treatments, policies, or exposures. It differes from an experiment in that the investigat

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

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

Planning clinical research requires many decisions. The authors of this book explain key decisions with examples showing what works and what does not.

A daily glass of wine prolongs life—yet alcohol can cause life-threatening cancer. Some say raising the minimum wage will decrease inequality while others say