This quote is from the ever quotable John Ioannidis, in a commentary of the disagreements about how to interpret the evidence linking salt intake and health.
“Sometimes I wonder whether published observational epidemiology is simply reflecting a power-weighted vote count of the opinions of epidemiologists. What does a risk ratio of 1.3 mean? Perhaps it means that those who believe in the risk factor have 1.3-fold more powerful opinions than those who don’t believe in the risk factor. In this (hypothetical) nightmare situation, risk ratios are accurate measures of epidemiologists’ net bias.
Systematic reviews cannot settle this conundrum after the fact. Even systematic reviews of randomized trials can reach almost any conclusion the reviewers believe in. “
Gary Taubes, talking about our understanding of obesity:
“Here’s another possibility: The 600,000 articles — along with several tens of thousands of diet books — are the noise generated by a dysfunctional research establishment.”
I think it was James Le Fanu who suggested that closing most UK departments of epidemiology and public health might result in a net gain to human health. So much research work is zombie science: you can’t kill it , because it is already dead ( I owe this formulation to Bruce Charlton). But the problem is not just with observational research. Ironically, it may have been the fact that Doll and Hill were right, that may have been, in the long term, a harmful influence on discovery.