In a new econtalk podcast, David Henderson and Russ Roberts discuss the issue of how a layman should deal with economic expertise. They mention the problem that the press will seek out "balance" when in fact one side is represented only by highly suspect spokesmen for lobbying organizations. They mention the problem that economists have an incentive to take strong ideological positions in order to get attention. So how can a layman decide who to trust?
I talked about that issue in this essay. With one exception, I think there is nothing that the public can look for in terms of a signal about economists. The best thing is to force economists to explain their arguments clearly in layman's terms, and then to evaluate the arguments on their merits. That means you have to know enough about economics to be able to distinguish a compelling economic argument from demagoguery.
The exception is this: when an economist known for one ideological leaning makes an argument that favors a different persuasion, that in itself should lend credibility to the case. For example, when relatively liberal (in the modern sense) Brad DeLong takes the pro-free-trade position in a debate, that deserves attention. By the same token, when conservative Greg Mankiw has nothing nice to say about the tax treatment of carried interest, that is a sign that those conservatives who want to retain the tax break are on shaky ground.