As economists have often pointed out, we pay doctors for quantity, not quality. As they point out less often, we also pay them as individuals, rather than as members of a team working together for their patients. Both practices have made for serious problems.

What about regular professionals, who just want to do what they do as well as they can?

We look for medicine to be an orderly field of knowledge and procedure. But it is not. It is an imperfect science, an enterprise of constantly changing knowledge, uncertain information, fallible individuals, and at the same time lives on the line. There is science in what we do, yes, but also habit, intuition, and sometimes plain old guessing. The gap between what we know and what we aim for persists. And this gap complicates everything we do.

You want to ensure people can do it right 99 percent of time. When we have to fire one of our surgical trainees, it is never because they dont have the physical skills but because they dont have the moral skills - to practise and admit failure.

We now have 30 percent, for example, of Medicare patients who are seeing doctors who are rewarded for doing this kind of work, like high blood pressure control. So, the Affordable Care Act has pushed this direction down the road.

What is the alternative to understanding the complexity of the world?

People who reach certain levels of frailty, more important than getting their mammogram, more important than getting their blood pressure tweaked, they're at high risk of falling. If they fall and break their hip, they not only die sooner, they die miserably.