Stephen Dubner writes about a professor of economics who makes zillions of dollars consulting. I’m not surprised by this, because my impression is that legal consulting is an extremely inefficient market. In several of the cases I’ve consulted on, the statistical expert (typically not actually a statistician) has been truly incompetent, in one case not being certified as an expert in the relevant area by the court, and in another case–which was truly memorable–dividing by N (the population size) rather than n (the sample size) in computing the estimation variance from a random sample. (I was really looking forward to the exchange with this guy in the courtroom–I mean, what could he say, he’s a sampling expert and divided by the wrong N?–but, like most cases, it got settled before reaching court.)
I can give other stories, but the key point is that lawyers hire incompetent statistical experts, even in cases that are important. It’s gotta be worth their money to hire better consultants, but presumably they can’t find them. Actually, I think that I’ve probably cost less than the opposing consultant in every case I’ve worked on, since, despite my high hourly rate, I’m trying to minimize my consulting hours, whereas I imagine that professional consultants are, if not trying to maximize hours, at least to keep their business going. But most clients don’t know to hire me (or the equivalent)–I think they pretty much get their consultants by word of mouth or through some casual search. (I still can’t figure out why the Gore team in the 2000 election hired a statistical consultant who had, as far as I know, never worked seriously on election data before, given that there are so many quantitative political scientists out there. (I don’t actually know who the Bush team hired, but since they won, I guess they got their retrospective money’s worth.))
So, anyway, to get back to the econ professor guy: it’s probably worth clients’ money to hire this guy–I imagine his team has a minimum level of professionalism that’s much better than what’s usually out there. Given the high stakes in many legal cases, and the relative simplicity of the statistical questions that arise, I’m surprised that clients can’t do a better job in finding competent statistical experts.