Arnold Kling is wondering why economists have so little influence in the White House. But it's not just the White House where they go unheard. A feature of the euro area's debt crisis has also been that economists' many ideas for solving the problem have been ignored. Economists' lack of influence is not a local US phenomenon.

Why is this?

One reason , I fear, is that voters just don't want to hear from economists. If you think the US deficit can be cut painlessly by cutting government spending without touching Medicare or Social Security, or by taxing the very rich alone, you'll not want to listen to people who say things aren't so simple. And if you think feckless borrowers and lenders should be punished, you'll not be interested in those who think that moral hazard is only part of the euro area's problem.

This is magnified by one of the curses of our age - narcissism. Too many people think that all that matters is their own opinion, and shut out the dissonance that economists should provide; in many contexts, the fundamental principles of economics are 'it's not that simple' and 'we can't be sure.'

It's further magnified by another problem - the media. As Dr Dr says:

News reports must be less than two minutes long and preferably attention grabbing. Information has to be condensed, ideally dramatically'There is no room for complexity, for untidiness. Just as the documentary is a simplification, so too is the news.

Such an approach is not value-neutral. It sustains a bias against social science.

However, economists' lack of influence isn't just a demand-side failure. There's also a supply-side problem. The predominant image the public have of economists is that they are forecasters. For years, whenever I told anyone I was an economist, the immediate reaction was: 'What's going to happen to my mortgage rate?' But of course, forecasts go wrong and so economists' reputation suffers.

In this sense, we economists present the very worst aspects of our discipline to the public. Which is the opposite of what the natural scientists do. Cosmologists invite us to wonder at their discoveries, whilst glossing over the fact that they haven't a clue what most of the universe consists of. And medics crow more about their latest cures than the fact that medical errors kill tens of thousands each year.

This, though, is no accident. Economists make forecasts for the same reason that Willie Sutton apocryphally robbed banks - because that's where the money is.

In this sense, economists' disrepute and lack of influence merely vindicates one of the fundamental insights of our discipline - that incentives have effects, and sometimes unintended and adverse ones.