More (#2) from Expert Political Judgment:

I have long resonated to classical liberal arguments that stress the efficacy of free-for-all exchanges in stimulating good ideas and screening out bad ones. But I now see many reasons why the routine checks and balances — in society at large as well as in the cloisters of academe — are not up to correcting the judgmental biases documented here. The marketplace of ideas, especially that for political prognostication, has at least three serious imperfections that permit lots of nonsense to persist for long stretches of time.

First, vigorous competition among providers of intellectual products (off-the-shelf opinions) is not enough if the consumers are unmotivated to be discriminating judges of competing claims and counterclaims. This state of affairs most commonly arises when the mass public reacts to intellectuals peddling their wares on op-ed pages or in television studios, but it even arises in academia when harried, hyperspecialized faculty make rapid-fire assessments of scholars whose work is remote from their own. These consumers are rationally ignorant. They do not think it worth their while trying to gauge quality on their own. So, they rely on low-effort heuristics that prize attributes of alleged specialists, such as institutional affiliation, fame, and even physical attractiveness, that are weak predictors of epistemic quality. Indeed, our data— as well as other work— suggest that consumers, especially the emphatically self-confident hedgehogs among them, often rely on low-effort heuristics that are negative predictors of epistemic quality. Many share Harry Truman’s oft-quoted preference for one-armed advisers.