In Marsh v. Valyou, the Florida Supreme Court (1)reiterated that Florida follows the Frye general acceptance test; (2) held that Frye doesn't apply to a medical expert's "opinion" testimony regarding causation; (3) held that even if Frye did apply, it should be applied only to the issue of whether the technique of "differential diagnosis" is generally accepted in the medical community, regardless of whether the technique was used in a generally accepted way; and (4) implicitly rejected the notion that Florida Rule of Evidence 702, modeled on the federal rule that led to the Daubert Supreme Court opinion, provides a "backup" reliability test for causation testimony.
In short, the Florida Supreme Court essentially held that any qualified medical expert (with qualifications always defined loosely) can testify to almost any causation theory, without any real judicial scrutiny. Florida law, then, has regressed to the pre-Daubert let-it-all-in stage, at least with regard to medical causation testimony. Florida thus joins Illinois and Kansas as states that have applied Frye so liberally as to make it virtually meaningless in cases involving causation disputes. The general argument is that only real scientific methodologies, not "pure opinion", are subject to Frye. As I've written, "this peculiar outcome seems to suggest that the less objective the basis for an expert's scientific opinion, the less judicial scrutiny it should receive!"
The dissent, written by Justice Cantero and joined by two other justices, is a model opinion, and eviscerates the majority's reasoning. The dissent could have found additional support in this article of mine on Frye, published at 41 Jurimetrics J. 385-407 (2001).
Interestingly, the national tort reform groups were absent as amici from this case, once again confirming that are dropping the ball when it comes to ensuring that the victories they won with the Daubert trilogy and amended Rule 702 aren't snatched away by permissive state court rulings.
I hope that Marsh will lead the Florida legislature to joins Georgia, Mississippi, and Michigan in adopted a state version of amended Rule 702 by statute. Otherwise, Florida will become a breeding ground for quackspertise.
[Cross-posted at the Volokh Conspiracy]
UPDATE: The best overall discussion of Frye out there is in my co-authored treatise, The New Wigmore: Expert Evidence. To give credit where it's due, David Kaye wrote this chapter.