Video: How Survival Rates Are (Very) Different from Mortality Rates

Think the U.S. has the greatest health care system in the world?

Over at The Incidental Economist, pediatrician, blogger and health researcher Aaron Carroll has posted a terrific video explaining why survival rates are not the best way to compare how well the U.S. system is doing against  that of any other country. Check it out:


Here’s the takeaway: the mortality rate is the number of people who die every year of a given cause in a specific number of people (often 100,000). The survival rate is how many people are still alive at a specific time after diagnosis.

Survival rates, Carroll explains, can be lengthened by preventing death, curing an illness or … diagnosing the disease earlier.

As he explains it, suppose there were a dread disease, cancer of the thumb. No one could detect it until they felt a lump. All got chemo, but four years later, anyone who got it was dead. That’s a five-year survival rate of zero.

Now suppose you had a super-duper scanner that could find that cancer of the thumb at the very first cell, say, five years before the patient would have felt a lump. The patients all get chemo. In other words, the treatments are unchanged. But the patients still all die four years after they would have felt the lump.

The five-year survival rate is close to 100 percent, but the mortality rate is unchanged.

Carroll also does a nifty comparison of breast cancer and prostate cancer in the U.S. and Great Britain. Sure, U.S. survival rates of both diseases beat the Brits. But, mortality rates? Not so much.