How Numbers Mislead

I met Kai Robertson for lunch earlier this week at Northside Social, a wonderful coffee house in Arlington, Virginia with a great sustainability theme running through its menu. Kai is with BSR and we were discussing a range of corporate responsibility and sustainability issues.  While we were talking, I was approached by a reporter.

This was a great venue to be interviewed by a reporter from a local news channel, News 7 – On Your Side, about my views on coffee.  I was asked how my coffee drinking habits would be influenced by knowing that a new study indicates that chances of head and neck cancer are possibly reduced by 40% for drinkers of more than four cups of caffeinated coffee a day.  I drink about three cups of caffeinated coffee a week right now and a decaf once or twice a day.

Until Monday I didn’t walk around worrying about head and neck cancer, but a 40% improvement in my chances sounded attractive so I took a caffeinated cappuccino to go although it kept me awake that night!

The published article explains that The American Cancer Society estimates more than 36,000 new cases of these cancers will be diagnosed this year in the USA. So by my reckoning a 39% reduction in risk would result in only 21,960 new cases.

But to achieve that, I, and the whole 300,000,000 population of the USA has to drink four cups of caffeinated coffee a day. My personal risk factor would go from 0.012% to 0.0073%.

On balance I think I will stick with my gut reaction on the interview “If anything, I’m probably more conscious of not drinking too much because I don’t want too much caffeine,” and also, stick with my current consumption.

‘News 7 – On Your Side’?  Based on their approach to this research I am not so sure!


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