In this issue: "NNT" -- What It Means and Why You Should Care; Finding NNT's for Any Condition; and Eye-Popping NNT's for Breast Cancer Screening.

Every single recommendation you will ever get for health care -- at least if it's grounded in science, not fantasy -- depends on numbers. How many people live, and how many people die, if they get Treatment A, and what difference if they get Treatment B? That's what most medical researchers do: Count human lives and compare groups to see what works and what doesn't work.

The trouble is that medical news is chock-a-block with intimidating numbers that are hard for a lay person to sort out. Worse, sometimes the sellers of new medical "breakthroughs" are actually trying to mislead and confuse you.

But now, we ride to the rescue with this: The One and Only Medical Statistic You'll Ever Need. It's called the Number Needed to Treat. This is a statistical idea that is simple and eye-opening. It will not only help you make truly intelligent health care decisions for yourself and your loved ones. It will also give you an idea of why American health care is so ruinously expensive.