So said Dr. Steven M. Asch, a health care researcher at the V.A. Greater Los Angeles Health Care System and the RAND Corporation in Santa Monica.

He was quoted in Gina Kolata's Saturday New York Times front-page story about how highly-regarded hospitals and physicians surprisingly often fail to follow well-accepted practice guidelines.

I've always been puzzled as to how medicine became structured such that a terrible doctor makes as much as - and in some cases much more than - an excellent one.

What gives?

How is this possible?

It's because there's really no way of assessing who's good and who's not.

Most things in medicine are routine, and so it doesn't matter who does them.

For the hard parts, well, any one patient generally only has one experience to report.

But to whom?

Family and friends?

And even then, what good is a series of one?

It's like the doctor who says, "In my experience..." when he's only done something once or twice.

Doesn't give you a whole lot of confidence in predicting future outcomes, does it?

The difference between a good or a bad doctor is so subtle to a civilian/patient, you'll never be able to know for sure.

Doctors know.

But for the most part, they won't trash a fellow physician.

And even bad doctors get away with their mistakes most of the time with no harm done: the human body is surprisingly forgiving, and gets over most things with or without medical intervention.

Now Medicare's starting to rate hospitals based on how often they use proven remedies for common ailments.

Within a few years, individual doctors are going to be rated as well.

That's the thrust of Kolata's article.

But I have a secret to let you in on: those ratings will not tell you whether the doctor who's treating you is any good or not.

Zero relationship.