At an alcohol conference in Ireland, a clinician colleague commented from the lectern that the UK safe drinking guidelines were “Puritanical” because “Me and my mates like to go out and have 4 or 5 pints on Fridays — how could that be hazardous?”. A fairly similar comment was related to me by a reporter recently, more along the lines of asking why public health guideline writers are such killjoys when it comes to have having a few extra drinks around Christmas.
This is one of two common misunderstandings about epidemiologic information, namely that it contains some moral judgment. If you drink X units of alcohol, you can look on a ginormous chart and see your group’s average outcomes on a range of variables, including heart attacks, longevity, accidents and so forth. The data don’t care if you live more or fewer years, yet many people look at them as a moral compass or rebuke.
The other widespread misunderstanding of epidemiologic information is the conflation of population averages with the outcomes of individual cases. When the U.S. Preventative Services Task Force announced that routine mammograms could be delayed until a woman is age 50, I knew they were going to get eviscerated in the media by powerful individual stories, e.g. “I had a mammogram at age 41 and that’s why I am alive so how dare you put out guidelines that would murder women like me!”. Trying to explain a complex epidemiologic conclusion in the press while being challenged by a vivid, easy to understand individual story is absolutely hopeless.
Because public policy decisions often have to be guided by epidemiologic information, some people have called for better science education in K-12 so that more Americans can understand epidemiology. A noble goal, but probably a quixotic one. In popular discourse, we tend to get sucked in by individual stories, and ’twill always be thus. For me this is just a case of why it is good to have a republic and not a democracy.