David Kaye has this essay in Michigan Law Review First Impressions on the DNA testimony at issue in McDaniel v. Brown. Our prior posts on the case are here, here, and here.

Kaye's essay is a balanced look at the trial testimony and what Brown's attorneys and the Ninth Circuit have said about it. The bottom line, as I read it, is that although the expert did err in response to questions from counsel, the errors are not as prejudicial as Judge Wardlaw's overheated opinion makes them out to be.

I especially enjoyed Kaye's mild rebuke of the opinion for referring to Bayes' Theorem as a "complicated formula."

But Bayes' theorem is not a "complicated formula." It is derived in nearly every introductory text on probability or statistics. It has been discussed ad nauseum in law reviews. It states that the probability of a hypothesis changes with new information in the following simple way: posterior odds = likelihood ratio × prior odds.

As one of the few lawyers with a scientific undergraduate degree, I am often appalled at how little math it takes to make some lawyers throw up their hands and declare the matter too complicated for their comprehension. Anything past the fourth grade level seems to do it.

Anyhow, I doubt the Supreme Court's decision will actually turn on a discussion of the DNA. As noted in our prior posts, the petitioner abandoned the theory he prevailed on in the Ninth Circuit, and the Supreme Court took the case off the argument calendar. I'm betting on a "vacate, remand, and do it right this time, dummies" order.

Update: From David Kaye by email: "By the way, at a conference at George Washington University, when I read the part of the Ninth Circuit opinion on how 'complicated' Bayes' Theorem is, the assembled statisticians broke out in laughter."