Over at Edge, a variety of scientists give their take on the Iceland volcano eruption and its impact on air travel. Two really stood out to me. The first also highlights the problem of defensive medicine; the second shows the downside to action dealing with global warming:

DANIEL KAHNEMAN

Psychologist, Princeton; Recipient, 2002 Nobel Prize in Economic Sciences

Imagine a public official who considers an action that involves a small and ambiguous risk of disaster. Imagine further that the best expert judgment available is that the expected social benefit of the action is large and that the risks are real but tolerably small. Such situations inevitably create a conflict between the interests of society and those of the officials who are charged to decide on its behalf.

Hindsight and personal accountability are the problem. Decision makers can be certain that if the worst happens their decision to act — however justified it was ex ante — will be perceived ex post as a horrendous mistake. They face the possibility of devastating blame and guilt, as well as career-destroying consequences. The risks are asymmetric because the costs of playing it safe are likely to be negligible.

Even if future analyses of the ash cloud incident conclude that flights could have resumed safely much sooner, it is unlikely that any of the officials involved in delaying the flights will lose their jobs. In this situation and in many others — defensive medicine is an example — the valid anticipation of hindsight combines with social norms of personal accountability to produce overly cautious behavior.

The solution?

Where the social good requires taking risks, we need procedures that will reduce personal accountability and diffuse responsibility, perhaps by assigning some categories of decisions to designated groups of experts rather than to individual functionaries.