Friday, June 30, 2006

Who's Smarter? The FDA or the Surgeon General?

Some states have adopted a presumption of nondefectiveness (rebuttable or otherwise) for FDA-approved drugs and/or medical devices. Some "tort reformers" have even proposed that such a presumption be imposed on the states, preemptively, by federal statute. Personally, we think that would probably be a bad idea, for reasons ranging from the nature of the FDA approval process to considerations of federalism. But reasonable minds could differ.

We got to thinking, though. Shouldn't those advocating such a presumption also advocate, with equal zeal, a parallel presumption in favor of federal agency findings that support a generic causal link between some substance or product and disease -- e.g., the recent Surgeon General's Report linking second-hand smoke to various adverse health outcomes, even at the lowest exposures?

If not, why not? If anything, isn't the policy rationale for a presumption arguably stronger, for something like the Surgeon General's comprehensive study, than for the more provisional assessments of risk in initial FDA approvals?

And wouldn't a presumption in favor of agency findings of generic causation drive down the costs of litigation, by eliminating a host of frivolous Daubert motions?

Update 7/2/06: We've asked a "good question," says Prof. Childs.

First Circuit Gives Vocabulary Lesson, Upholds Slip and Fall Testimony

Using the words "encincture" and "tribologist," the First Circuit has upheld a district court's decision admitting a mechanical engineer's testimony about a defective swimming pool stairway in a slip-and-fall case. See Santos v. Posadas de Puerto Rico Assocs., Inc., No. 05-2070 (1st Cir. June 29, 2006).

Update 6/30/06: We're not the only ones who noticed the big words.

Thursday, June 29, 2006

Due Process Clause Does Not Guarantee Right to Present Expert Evidence on Mens Rea

The Supreme Court held today, in Clark v. Arizona, No. 05-5966 (U.S. June 29, 2006), that the Due Process Clause is not offended by a state evidentiary regime permitting expert testimony in support of an insanity defense but barring its use to negate mens rea.

Press coverage undoubtedly will focus mostly on today's other Supreme Court disposition, in Hamdan v. Rumsfeld, No. 05-184 (U.S. June 29, 2006). But in terms of practical realities in the day-to-day administration of justice in this country, the Clark decision may well be the more significant.

We'll have more on Clark after we've studied the decision more carefully.

Update 6/30/06: Here's today's SCOTUSblog writeup on Clark.

Update 7/8/06: And here's Emily Bazelon's take in Slate.

Blog 702 Turns Three

Today marks three years of blogging for us. Wish us happy birthday!

Tuesday, June 27, 2006

O'er the Land of the Free

Methodological Rigor and Lethal Injection

As the St. Louis Post-Dispatch and other media sources are reporting, U.S. District Judge Fernando J. Gaitan, Jr., ordered a halt to Missouri executions yesterday, pending the state's development of some semblance of a formal protocol to ensure that the condemned don't suffer unconstitutionally gratuitous pain. We were curious about the expert testimony Judge Gaitan may have considered, and so we dug up a copy of yesterday's opinion in Taylor v. Crawford, No. 05-4173-CV-C-FJG (W.D. Mo. June 26, 2006), which we herewith post for our readers' edification.

It is not for the squeamish. The state follows the usual three-drug regimen. A physician first administers a dose of sodium pentothal, a.k.a. thiopental, as an anesthetic. Pancuronium bromide is them administered as a paralytic agent. A third and final drug, potassium chloride, stops the heart. Only the anesthesia prevents the condemned from suffering excruciating pain when the third drug is administered.

There is no written protocol governing lethal injections in Missouri. Doses are left to the discretion of the physician who mixes the drugs. Judge Gaitan permitted the deposition of that physician to be taken. He is a board-certified surgeon, but not an anesthesiologist. He is dyslexic, so he frequently transposes numbers even while staring at them, but he says this does not affect his usual work as a surgeon. His practice had been to use a 5 gram dose of sodium pentothal, the anesthetic. Recently, however, the state has been obtaining sodium pentothal from a different supplier, and the physician has been using a dosage of 2.5 gram, because of difficulty dissolving much more than that amount in the volume of liquid that the syringes will hold. Pending some solution to that problem, the physician is, as he put it, "improvising."

The physician does not administer the drugs himself. That is done by nonmedical personnel, "and they're in the dark so they have a small flashlight that they're able to quickly identify the syringes, make the appropriate connections and injections, disconnect, and clamp the tube."

The physician is responsible, however, for monitoring anesthetic depth. He does this by viewing the condemned's facial expression. "[I]t’s difficult to describe, but I can tell instantly when the pentothal has taken effect. And in medical practice the instant the pentothal has taken effect they gave absolutely no more because then they move on to the actual anesthesia which has to be started before the pentothal wears off." From a videotape of the execution facility, Judge Gaitan found it would be nearly impossible for the physician to observe the inmate's facial expression. The inmate, at that point in the process, is strapped to a gurney in the execution chamber, across the room and facing away from the operations center, from which the physician is viewing the proceedings through a window obscured by partially closed blinds.

Monday, June 26, 2006

Liberal Law Professor Crashes Manhattan Institute's Gates

In what may prove a laudable show of tolerance for heterodoxy, Point of Law has invited Prof. Bill Childs, a self-described "progressive Democrat" who teaches at the Western New England College School of Law and also writes TortsProf Blog, to guest-blog for a week on a subject he calls "Tort Reform for Liberals." His inaugural post suggests that he will focus largely on the use and abuse of science in litigation.

Saturday, June 24, 2006

The Year So Far

Some updated numbers:

  • Federal appellate opinions so far in 2006 addressing the admissibility of expert evidence under Rule 702: 52
  • Projected opinions to be rendered this year at that pace: 108
  • Average per annum from 2000 through 2005: 132
  • Decisions this year in which a district court's evidentiary ruling was held to be error: 2
  • Decisions in which an erroneous district court ruling led to reversal of the judgment: 0
  • Number of dissents in this year's opinions to date: 0
  • Number of this year's opinions published to date: 21
  • Percentage published, year to date: 40.4
  • Percentage published, 1/1/2000 to date: 58.7

Friday, June 23, 2006

How to Liven Up the "Tort Reform" Discussion

Bored with the meticulous logic and close empirical analysis so prevalent in debates over "tort reform"? An editorial from The Oklahoman offers a solution so breathtakingly simple, we're surprised nobody has thought of it before:
"To grasp the importance of lawsuit reform, sometimes it’s useful to start with an anecdote and move to a conclusion."

Thursday, June 22, 2006

Ninth Circuit Issues Major Opinion on Penile Plethysmograph Testing

Penile plethysmograph testing involves measuring a subject's erectile response to different sexually stimulating images -- to determine, e.g., whether the subject is aroused by sexual images of children. Courts have held the procedure insufficiently reliable to qualify for admissibility in trial proceedings, but the testing is often imposed on sex offenders as a condition of supervised release. The Ninth Circuit has now issued a major opinion holding that it may not be, under the governing federal statutory regime, unless the district court has first made a thorough, on-the-record inquiry into whether the testing is reasonably necessary in the particular case to promote the goals of deterrence, rehabilitation, or protection of the public, given the availability of less intrusive alternatives. See United States v. Weber, No. 05-50191 (9th Cir. June 20, 2006) (Canby, Noonan, & Berzon, JJ.).

Although the court's opinion does not adopt a per se ban, it makes plain the court's expectation that the testing will not be imposed as a matter of routine. Judge Berzon's opinion begins with the observation that "one would expect to find a description of such a procedure gracing the pages of a George Orwell novel rather than the Federal Reporter." Judge Noonan's two-paragraph concurrence goes further:
Judge Berzon's excellent opinion is deserving of support. I would, however, go beyond it to hold the Orwellian procedure at issue to be always a violation of the personal dignity of which prisoners are not deprived. The procedure violates a prisoner's bodily integrity by affecting his genitals. The procedure violates a prisoner's mental integrity by intruding images into his brain. The procedure violates a prisoner's moral integrity by requiring him to masturbate.

By committing a crime and being convicted of it, a person does not cease to be a person. A prisoner is not a mere tool of the state to be manipulated by it to achieve the purposes the law has determined appropriate in punishment. The prisoner retains his humanity and therefore has purposes transcending those of the state. A prisoner, for example, cannot be forced into prostitution to aid the state in securing evidence. A prisoner, for example, cannot be made to perjure himself in order to assist a prosecution. Similarly, a prisoner should not be compelled to stimulate himself sexually in order for the government to get a sense of his current proclivities. There is a line at which the government must stop. Penile plethysmography testing crosses it.

Wednesday, June 21, 2006

Kentucky Supreme Court Upholds "Homicide by Heart Attack" Testimony

The Kentucky Supreme Court has upheld testimony from a medical examiner who opined in a manslaughter trial that the cause of death was "homicide by heart attack." See Baraka v. Commonwealth, No. 2004-SC-0256-DG (Ky. June 15, 2006).

Tuesday, June 20, 2006

Testimony on Defective Tires Was Itself Defective, Says Texas Supreme Court

After conducting a searching review of plaintiffs' expert testimony and finding it unreliable, the Texas Supreme Court has reversed an $11 million verdict in a tire defect case involving a rollover and four fatalities. See Cooper Tire & Rubber Co. v. Mendez, No. 04-1039 (Tex. June 16, 2006).

Monday, June 19, 2006

More on Medical Malpractice and Professional Judgment Calls

Ted Frank has responded to our post from yesterday, amplifying his views on malpractice liability arising from "reasonable" professional judgment calls. In his latest post, Frank focuses on the differences beween medical malpractice litigation, where Frank says doctors often get held liable for making reasonable treatment decisions, and legal malpractice cases, where he says the lawyers get more slack.

Update 6/20/06: Ted Frank has now posted a further response, focusing on our point about the different levels of economic deterrence for bad decisions in business versus medicine. We're not sure Frank has completely grappled with the issue of economic incentives. It's true that some directors have only a modest financial stake in the enterprise. But many have a substantial one, and of course there's never a perfect match between the application of a legal rule and the underlying policy rationales for the rule.

Meanwhile, larger economic forces are also in play. One foundational premise of a capitalist economy is that the invisible hand of the marketplace will incentivize the enterprise as a whole to pursue a rationally profit-maximizing course. Malpractice exposure apart, are there really comparable market pressures for health care institutions to make health-maximizing decisions? We're just asking.

Update 6/21/06: Ted Frank has posted a still further response that seems to us to change the subject. The original question posed by Frank was why the law shows more deference to business decisions (the "business judgment rule") than to medical ones. We noted that one reason sometimes floated for special deference in the business context involves the notion that the market itself may often be a sufficient corrective for bad business decisions. We don't necessarily agree that this is a persuasive justification for the business judgment rule. But it is a plausible difference between the business and medical contexts. Frank tries to analogize the two contexts by arguing that just as the interests of physicians and patients are "imperfectly" aligned, so too are the interests of corporate directors and the enterprise. But he does not address the comparative degrees of imperfection. Instead, Frank now says "the question" is whether malpractice doctrine creates "better incentives" than would prevail in the doctrine's absence (or under some adjusted version).

Well, that's admittedly one question. But it's not the question Frank originally asked, and it's not the one to which we had been responding.

Sunday, June 18, 2006

A "Business Judgment Rule" for Medical Malpractice?

Ted Frank has posted some observations on a $30 million malpractice verdict in Philadelphia, and on what the verdict may imply about strategies for "liability reform." He notes that even caps on non-economic damages would not have reduced the verdict below $15 million, and concludes that "[r]eal reform needs to be aimed at improving the quality of the evidence jurors hear and taking reasonable judgment calls out of malpractice."

In that vein, Frank wonders aloud about why malpractice law doesn't follow a standard akin to the business judgment rule:
[O]ne immediately recognizes problems when juries are asked to decide between two experts about the appropriate treatment course. If reasonable doctors disagree, both treatment courses should be considered non-negligent. Otherwise, one jury could find treatment A negligent, while another jury can find the alternative treatment negligent, and doctors are effectively blamed for any bad result. Yes, I know no court adopts a "business judgment" rule for medical malpractice, though this sort of discretion is given attorneys in legal malpractice cases. But why not?
Those who need a brief refresher course on the business judgment rule (as we did) may want to take a peek at Professor Bainbridge's 2003 paper, "The Business Judgment Rule as Abstention Doctrine." On doing so, the reader will learn (or remember) that some commentators consider the business judgment rule itself to afford inadequate protection for corporate directors, at least as some courts apply the doctrine. Bainbridge identifies two competing conceptions of the business judgment rule in the case law. In one, the rule is seen as a special standard of liability, under which directors may not be held liable for merely negligent business decisions, but only for decisions breaching some more forgiving standard of care (whose precise nature and contours remain subject to considerable indeterminacy and debate). In the other, the rule is seen as one of judicial abstention. The latter conception may be the more director-friendly, as it prevents more controversies from reaching the trier of fact.

Frank's post is presumably meant to spark thought, not to provide a finished solution, and so Frank doesn't spell out the specific features that a malpractice analogue to the business judgment rule should have. A clue may be afforded, however, by his ideas about what should happen if two "reasonable doctors" could differ on the appropriate course of treatment. In that circumstance, Frank suggests, either course of treatment should be considered non-negligent.

We say that Ted Frank's language affords only a "clue" because some of the complexities may be obscured in his shorthand formulation. To tease them out, let's focus on the phrase "reasonable doctors." The reasonableness requirement, we take it, would actually apply not to the doctors considered as persons, but to their opinions on the appropriate course of treatment. On that interpretation, Ted Frank's proposal could come in any of at least three flavors:
  • If the jury considers the course of treatment pursued by the malpractice defendant to have been one "reasonable" choice among the alternatives, then the jury should render a verdict for the defendant on liability, even though the defendant's "reasonable" acts may not have conformed to the standard of care normally offered in the relevant community.

  • If a malpractice defendant can call a witness whose exculpatory opinion on breach of duty is sufficiently "reasonable" to satisfy prevailing standards for the admissibility for expert testimony, then judgment should be rendered for the defendant, even if the claimant produces an expert with an admissible opinion to the opposite effect.

  • If a court should determine, on weighing the facts itself, that the malpractice defendant selected a course of treatment within the range of "reasonable" options, then it should dismiss the suit.

It seems fair to assume that Frank would not propose the first variant, which would essentially detach the jury's appraisal of "reasonableness" from any obvious objective moorings, with the probable result of increasing rather than reducing medical malpractice exposure. The second variant seemingly amounts to a proposal that the existence of genuine factual dispute on the blameworthiness of the defendant's conduct should result in dismissal of the claims. That idea, to be candid, makes our heads spin, and we'd have to take another look at the Seventh Amendment before commenting much further. But perhaps the third variant is closest to what Frank is proposing, possibly in tandem with a more provider-tolerant "reasonableness" standard. Such a regime might be seen as procedurally analogous to the "abstention" model for the business judgment rule.

There may be Seventh Amendment issues with the third variant too, but let's leave those aside for now. What interests us more, at the moment, is whether any of these three variants could be tied to some acceptable standard for "reasonableness" that would represent a clear improvement on the current regime from the standpoint of promoting consistent results that could also be accepted as falling within the broad limits of fairness and justice.1

We're skeptical. It's far from obvious, in particular, that merely adopting a more mistake-tolerant duty of care would turn the trick. Suppose, to pick an extreme example, that reasonableness were redefined, in the malpractice context, to require only an absence of "intentional or reckless" misconduct (as may be the actual agenda of some). In the first "reform" variant under consideration, the jury would still decide the issue in cases of genuine dispute, and so the possibility of successive verdicts imposing inconsistent standards of treatment would remain.2 In the second variant, the revised liability standard might put something of a dent in the supply curve for plaintiff-friendly malpractice experts. But under any liability standard, the second variant seemingly poses an unacceptably high risk of increasing variability of outcomes, because it would lash liability determinations to the tempest-tossed mast of discretionary evidentiary rulings (although admittedly, Ted Frank wants to "reform" those too). Under the third variant, no doubt, a new provider-friendly duty of care would do something to reduce the number of jury trials, and therefore, perhaps, to reduce, by brute statistical force, the risk that successive verdicts would impose inconsistent standards of care. But the third variant also implies a high level of trust in the judiciary's capacity to develop, through the process of stare decisis, a consistent and coherent body of decisions supplying a working definition for the liability standard. If that process hasn't worked to tort reformers' satisfaction in producing consistent and acceptable results under the current negligence regime, there may be dubious grounds for optimism that the situation would improve with a redo.

Concededly, any measure that reduced the volume of jury trials in malpractice cases would tend, ceteris paribus, to increase the domain of safely liability-free provider conduct -- just as reducing the number of highway patrolmen improves the odds of avoiding a speeding ticket. Our point is that changing to a stricter or more lenient standard won't necessarily do much to make inconsistent outcomes go away. And if the mere memory or possibility of traumatic outcomes is as powerful a precipitant of insurer agoraphobia as Ted Frank seems to think, we might still end up living in a world of PTSD-governed premiums.

Meanwhile, in response to Frank's question why no court has adopted the business judgment rule in the malpractice setting, we wonder if it doesn't have something to do with an argument in favor of the business judgment rule we seem to remember hearing, to the effect that efficient markets make litigious regulation of corporate behavior largely superfluous. Corporate officers and directors have an inherent incentive to make good business decisions, because their economic fortunes are tied to those of their companies -- or so goes the argument. Malpractice exposure apart, what is the parallel economic incentive for health care providers?


1 The caveat about outcomes falling acceptably within the bounds of fairness and justice is a necessary one. If consistency were the only goal, it would be trivially simple to design a foolproof system -- e.g., one in which all malpractice plaintiffs automatically win, or one in which all malpractice plaintiffs automatically lose.

2 As judicial interpretation of the new liability standard developed, a greater number of cases might be taken from the jury on summary judgment, in which event the statistical risk of successive verdicts imposing incompatible standards of conduct might be reduced. If that is what Ted Frank has in mind, then the first variant, in combination with a new and more provider-friendly standard for liability, would begin to share many features with the third.

Tuesday, June 13, 2006

10th Circuit Issues Decision on Expert Evidence re Eyewitness Testimony

We've learned somewhat tardily that on June 2, the Tenth Circuit issued a significant opinion about expert testimony on the fallibility of eyewitness identification. The opinion continues to reject a per se ban on such expert testimony, but concludes that it is likely to assist the jury in only a narrow array of circumstances -- e.g., in cases involving "cross-racial identification, identification after a long delay, identification after observation under stress, and [such] psychological phenomena as the feedback factor and unconscious transference." See United States v. Rodrigez-Felix, No. 05-2142 (10th Cir. June 2, 2006) (Lucero, McWilliams, & Tymkovich, JJ.).

Saturday, June 10, 2006

Federal Judge Issues TRO Barring AANS from Sanctioning Expert Witness

United States District Judge Ralph Tyson, sitting in Baton Rouge, has issued a temporary restraining order barring the American Association of Neurological Surgeons from sanctioning a Louisiana neurosurgeon for testifying as a plaintiff's expert witness in a Florida malpractice case. The AANS wants to suspend the neurosurgeon for two years because he "demonstrated a lack of adequate subject matter knowledge and acted as an advocate for the plaintiff and the plaintiff attorney rather than as an unbiased witness." The Baton Rouge Advocate has the story.

Update 6/13/06: Here's the actual Temporary Restraining Order. We're not First Amendment lawyers. But the TRO appears to us to go beyond enjoining disciplinary sanctions, and toward the realm of prior restraints.

Friday, June 09, 2006

8th Circuit Upholds Exclusion of Design Defect Testimony

Yesterday, the Eighth Circuit upheld the district court's exclusion of a plaintiff's expert testimony that a hay baler was defectively designed because it failed to incorporate certain safety features. The plaintiff was injured when he was attempting to clear blockage at the intake point:
While baling hay on July 10, 2001, Wagner noticed that the baler had stopped accepting hay. With the power supply to the baler still engaged, Wagner stepped off the tractor and approached the baler to investigate. Wagner leaned over the baler frame and placed his left hand in hay that was covering the baler's pick-up tines. The tines suddenly began to move, and Wagner's hand was pulled into the baler's compression rollers. After the passage of some time, Wagner elected to self-amputate his left hand.
(Only someone from the legal profession could write that last sentence.)

The plaintiff's two experts suggested that a safer alternative design would have incorporated a safety rail at the intake point, an open-throat intake, and an emergency stop device. On summary judgment, the district court marched this testimony through the "Daubert factors" and found it thin on testing, peer review, and general acceptance. The Eighth Circuit's opinion upholds the exclusionary ruling as within the trial court's wide discretion. See Wagner v. Hesston Corp., No. 05-3232 (8th Cir. June 8, 2006) (Murphy, Bowman, & Benton, JJ.).

Wednesday, June 07, 2006

NC Court of Appeals Overturns Medical Board's Suspension of Expert Witness

A state court of appeals has reversed a Florida neurologist's suspension by the North Carolina Medical Board for giving unwelcome testimony in a medical malpractice case. The Charlotte Observer has the story. For the appellate opinion itself, see In re Lustgarten, No. COA05-891 (N.C. Ct. App. June 6, 2006).

Update 6/27/06: The Daily Business Review now has more extended coverage, via, via The Legal Reader.

Tuesday, June 06, 2006

Nebraska Supreme Court Reverses Exclusion of Differential Diagnosis Testimony that Trauma Caused Fibromyalgia

Last Friday, the Nebraska Supreme Court held that a trial court should have admitted testimony from experts who opined, based on a differential diagnosis, that a plaintiff's fibromyalgia was caused by her automobile accident. The court said that although the generic causal link between trauma and fibromyalgia is subject to heated medico-scientific dispute, there is enough support in the peer-reviewed literature for a physician to "rule in" trauma as a potential cause. The high court also held that the experts took sufficient steps to "rule out" other causes. The opinion was unanimous. See Epp v. Lauby, 271 Neb. 640 (Neb. 2006).

Daubert and Scientific Revolution

Daubert may work fine in times of "normal science."

But what if there's a change in paradigms?

Sunday, June 04, 2006

Tort Reform Database

For some time now, we've been privately lamenting the seeming absence of any readily available, canonical source that systematically compiles state "tort reform" provisions. Now an attempt has been made to fill the gap. Via TortsProf Blog, we learn of an SSRN paper in which Prof. Ronen Avraham, of Northwestern University Law School, has compiled a Database of State Tort Law Reforms. From the abstract:
This manuscript contains the most detailed, complete and comprehensive legal dataset of tort reforms in the U.S. The dataset records state laws in all fifty states and the District of Columbia over the last several decades. For each reform we record the effective date, a short description of the reform, whether or not the jury is allowed to know about the reform, whether the reform was upheld or struck down by the states' supreme courts, as well as whether it was amended by the state legislator. Previous and current scholarship which studies the empirical effects of tort reforms uses various different legal datasets .... Besides being different from each other, these datasets frequently do not cover reforms adopted before 1986, miss reforms superseded after 1986, miss court-based reforms, ignore effective dates of legislation, and do not accurately record judicial invalidation of laws. It is possible that at least some of the persisting variation across empirical studies about the effect of tort reforms might be due to variations across legal datasets used.... It is hoped that by creating one "canonized" dataset our understanding of the impact of tort reform on our life will increase.

Minnesota Supreme Court Issues Opinion on Gang Testimony

The Supreme Court of Minnesota has issued an opinion on expert testimony on gangs. The specific context is a Minnesota statute specifically criminalizing murder "for the benefit of a gang," and the opinion's specific ruling is that the unobjected-to testimony in the particular case was not plain error affecting the defendant's substantial rights. The decision nevertheless contains a lengthy analysis of factors pertinent to the admissibility of gang testimony -- a genre that the opinion views with some suspicion. The decision thus has potential value as persuasive authority in other contexts and jurisdictions. See State v. Jackson, No. A05-66 (Minn. June 1, 2006).

Friday, June 02, 2006

Federal Circuit Upholds Testimony Based on Computational Fluid Dynamics (CFD) Analysis

Yesterday, the Federal Circuit published a decision upholding expert analysis based on Computational Fluid Dynamics modeling. It held that CFD analysis is generally recognized as valid in the scientific community, and that the expert's choice of parameters went to weight, not admissibility. See Liquid Dynamics Corp. v. Vaughan Co., No. 05-1105 (Fed. Cir. June 1, 2006) (Gajarsa, Dyk, and Prost, JJ.).

Thursday, June 01, 2006

"Managerial Justice in a Post-Daubert World"

Sandra Gavin, a visiting Assistant Professor at Rutgers School of Law, has published an article on the erosion of the adversarial model in favor of a "managerial" style of judicial dispute resolution in the wake of Daubert and the Supreme Court's Celotex trilogy. See Sandra F. Gavin, Managerial Justice in a Post-Daubert World: A Reliability Paradigm, 234 F.R.D. 196 (2006). She urges adoption of a requirement for adversary hearings for Daubert motions with potentially dispositive consequences. For the abstract, and a Westlaw link, wander on over to the Federal Civil Practice Bulletin, which you should probably be reading anyway.
Fed. R. Evid. 702: If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.