Science Can Quantify Risks, But It Can't Settle Policy [NPR.org]

Suppose you're a 45-year-old woman living in the U.S. You have no history of breast cancer, nor worrisome symptoms. Should you have a mammogram?

If you follow the American Cancer Society's recommendation, the answer is "yes": You should begin routine mammography screening for breast cancer at age 45. But if you follow the U.S. Preventive Services Task Force recommendation, the answer is "no": You should probably wait another 5 years.

Which recommendation is right?

Answering this question goes well beyond the evidence. It's not just that the evidence is imperfect (though it always is). Rather, it's that turning evidence into policy requires more than empirical facts; it also depends on values. In this case, recommendations could differ depending on how much value is placed on avoiding "false alarms" — cases in which a mammogram leads to subsequent tests or treatments that are ultimately unnecessary — versus the value of preventing "misses," or cases in which a cancer that could have been caught by routine mammography slips by.

[For more of this story, written by Tania Lombrozo, go to http://www.npr.org/sections/13...-can-t-settle-policy]