20 marzo 2015
Many public health researchers take advantage of ‘natural experiments’ — comparing people’s calorie consumption or physical activity levels, either before and after a policy or environmental change, or in contrast to a similar group of people not affected by that change. But not all natural experiments are created equal. A public health team has now systematically reviewed the state of the science.
http://feeds.sciencedaily.com/~r/sciencedaily/~3/LStj6Mj1t5w/150320155654.htm
