A discussion I had earlier today reminded me of an argument I’ve had with friends in the scientific community on multiple occasions. The argument revolves around the belief that conclusions of science, such as the effect of cholesterol on heart disease, suggests specific interventions, such as reducing the dietary fat that we believe causes high cholesterol. In essence, we debate the means by which new scientific evidence should be used to influence public policy and private behavior. Taking strong evidence of a specific causal link between a cause and an undesireable outcome as prescription for a population intervention to remove the causative factor is fraught with danger. There are many reasons for this, but the two most salient are confounding and the law of intendended consequences.