Expertise and sensible opinion

Non-experts can have valuable opinions. But expert opinions are different. And being an expert in one area doesn’t entitle you to express an expert opinion in another.

Mark Thoma raises an important question about my discussion of the limits of academic expertise. Surely he is right to say that experts in one area can establish credentials to be heard in another area.

Sometimes that just means applying critical intelligence to make sense of facts gathered and theories propounded by experts in the new field; sometimes it just means carefully reading arguments and finding their flaws. Those can be valuable. If I didn’t believe that, I couldn’t justify blogging. Rarely, it means genuinely becoming an expert on something that wasn’t your original specialty.

But in any case, that claim to be heard needs to be established, not assumed, and its reach and depth need to be assessed, as opposed to assuming that anyone whose first name is “Professor” has an automatic entitlement to a respectful hearing for his random opinions.

To take Thoma’s example: Paul Krugman’s opinions about the rascality of the Bush Administration are valuable, and I mostly agree with them. But I feel perfectly free to disagree as an equal; he has no particular professional credential that deserves my deference. By contrast, I would be very, very cautious in disagreeing with Krugman about the effects of a proposed change in trade policy, since in that area he has expertise I lack.

Or, to take an example closer to home: On drug policy, I claim to speak ex cathedra. I know which arguments in the field hold water and which don’t, which empirical claims have been established by solid evidence and which haven’t, which opinions are within the bounds of reasoned discourse and which are mere flat-earthism. (Alas, much of current drug policy is based on flat-earth beliefs.)

Of course I could well be wrong on any given issue &#8212 having changed my mind several times on rather central points, I must surely have been grossly wrong either before or after the change &#8212 but anyone who hasn’t spent most of a lifetime studying the question would be rash to leap to the conclusion that he has seen some obvious truth that I have missed, or to assume that his sister-in-law’s experience is “reality” while all the empirical research in the area is “ivory tower speculation.”

By contrast, when I write about No Child Left Behind, I’m using no more than my ordinary knowledge of statistics and management, and my arguments are entitled to no more attention or deference than they earn by themselves. If my friend and colleague Meredith Phillips, who studies education for a living, tells me flatly that I’m wrong about something, my first guess is that I was, indeed, wrong, and my impulse is to retract the claim rather than trying to defend it.

Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact: