It’s a well-worn mantra: Correlation does not equal causation. But even if we know this, is it always accurately and responsibly reflected in our stories and headlines?
It can be simpler and more elegant to say “Vodka causes sexually transmitted infections” in a headline than “Vodka consumption associated with increased risk of sexually transmitted infections.” (Note: This is not a real headline or based on a real study.) But in this made-up example, it’s laughably obvious that vodka itself does not cause STDs. Continue reading
At some point almost all health care journalists will need to cover a medical study or two. When that happens, you’ll want to have at least a passing understanding of p values and statistics and you’ll need to know that correlation does not imply causation.
For a session on May 2, AHCJ’s medical studies topic leader Tara Haelle moderated a panel, “Begin mastering medical studies.” Haelle and two experts in the topic explained some of the finer points of covering studies: Ishani Ganguli, M.D., an assistant professor of medicine at the Harvard Medical School, and an internal medicine physician at Brigham and Women’s Hospital; and Regina Nuzzo, Ph.D., a freelance journalist and professor of science, technology and mathematics at Gallaudet University. Continue reading
The mouth is connected to the body.
Yet much remains unknown about the subtle workings of that connection.
Research continues to identify associations between oral and systemic conditions. But it is too soon to draw conclusions about possible causal relationships between maladies such as gum disease and cancer, warn the authors of a June guest editorial in the Journal of the American Dental Association. Continue reading
Image by Susan Sermoneta via flickr.
Two recent studies in the news have been clear examples of the correlation vs. causation question that’s part and parcel of covering observational research studies.
And they’re worth taking a look at because the correlations are inherently interesting, even though they almost certainly aren’t causal.
First up is “The Effect of Sexual Activity on Wages”, which was published by Germany’s Institute for the Study of Labor. Predictably, and probably in part due to its terrible title, this study generated lots of headlines like “Have more sex, make more money”, from The Wall Street Journal‘s Marketplace, and Cosmopolitan‘s “The More Sex You Have The More Money You Make“.
Well, not exactly. The study found an association between sex and wages. As self-reported sex increased, so too, did income. Of course, that doesn’t mean that having more sex causes people to make more money, a point that wasn’t stressed clearly enough in some articles for Scientific American blogger Evelyn Lamb’s tastes. Continue reading
You may have seen — and let’s face it — given a giant eye roll to a recent studythat claimed men who helped out with chores traditionally deemed the province of women, i.e. laundry, dishes, and dusting, had less sex than men who cut the grass and changed the oil but generally left the more feminine chores to their wives.
Health reporters cried foul.
One of the best ledes came from The Telegraph’s Michael Hanlon:
The relationship between sex, marriage and gender roles is so complex that unravelling it makes the work of the Large Hadron Collider look like playschool.
Hanlon’s story had plenty of strengths, including a quote from an expert who questioned the reliability of the data:
The fact is that people lie about, or at least misremember, how much housework they do almost as much as they lie about the amount of sex they are having.
His expert also pointed out that the two variables – sex and housework – might correlate, but may not necessarily be causal. Continue reading