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Understanding and spinning risk

In Evidence-Based Medicine on March 12, 2009 by Danielle Tagged: , , , , ,

Michael Blastland has written about/ created a useful tool for understanding the meaning of risk on the BBC Magazine website yesterday.  The key, he writes, is to “to ditch percentages and talk instead about the numbers of real people.”  Reading that bacon increases your [relative] risk of colorectal cancer by 20% is difficult to understand–it is better thought of as: 5 out of 100 people will have colorectal cancer in their lifetime, if all of these 100 people eat 3 extra rashers of bacon per day (the equivalent of 50g of processed meat according to the original 2008 news story), then one additional person will also have colorectal cancer, and the [absolute] lifetime risk rises to 6 out of 100 people.

Isn’t that factoid a lot less scary than the whopping 20% increase in colorectal cancer that was reported in the news?

For an in-depth discussion, please see the 2845 ways to spin risk posting in the Understanding Uncertainty blog.  They have a neato widget the allows you to state the risk positively or negatively, or as an absolute, relative, or ‘number needed to treat’ risk. My favourite is the positive absolute percentage: Your chance of avoiding bowel cancer, with bacon sandwiches, is 94%.” I am not statistically savvy, so this is highly educational.

If the small increase in risk attributed to scarfing the crispy, delicious stuff hasn’t put you off, you might be interested in this blog, dedicated to International Bacon Day.

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One Response to “Understanding and spinning risk”

  1. Excellent post Danielle. You ARE on a (bacon buttie) roll, aren’t you.

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