With tech, you pretty much know that each new generation of smart phone or laptop is going to be better: faster processing, better screen resolution, more apps -- more of everything.

Medical care doesn't work that way.

Not that you would ever know that from the steady drumbeat of breathless "breakthrough!" publicity from medical institutions. They want patients to think that the latest innovation really is the greatest. Often, it's not. Time and again, new treatments and tests offer no proven benefit to patients. They just cost a lot more.