Just a few days ago, a paper in the journal PLoS One, “Media Coverage of Medical Journals: Do the Best Articles Make the News?” showed how journalists are more likely to report on observational studies than on randomized clinical trials. The authors suggest this shows a systematic bias to report on weaker evidence.
And here’s one reason why that may happen.
This week the BMJ sent out a news release on a paper from the Annals of the Rheumatic Diseases, one of the specialist journals it publishes. And I’ve been waiting for days to address it – waiting for the journal’s embargo time to pass so that I’m not violating that sacred trust.
Nope. Sorry, BMJ news release writers. That’s an overstatement, to be kind. An inaccuracy, to be accurate. That’s not what the study showed, because it wasn’t equipped to show that anything “cut risk.” Proof of cutting risk would be proof of cause and effect. And the observational study in question can’t do that.
Don’t blame the authors of the journal article. They didn’t use cause-and-effect language. They concluded: “HRT is associated with an almost 40% reduction.” (My emphasis added.) That’s the way you describe the results of an observational study. That’s what we try to teach journalists and the public with a primer that’s been on our site for years. Maybe the BMJ should have its news release writers read it.
The researchers went even further, for any writer – journal news release writers included – who bothered to read the study. The research team wrote: “The main limitation of this study is its observational nature.”
To be clear, this was a large study with long followup. This could be a head-turner in medical circles.
But it still is what it is – a study that can only show statistical association.
And association ≠ causation.
We’ve written about this problem with BMJ news releases in the past, and will continue to do so until they get it right. Past examples:
As I wrote in one of these posts: Journals could help lift all ships – or they can (and sometimes do) help us all drown in a daily tsunami of global miscommunication about health news.
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