Resolving Daubert Challenges
Rule 56 -- Motions for Summary Judgment
Defendants have learned to serve Daubert motions in tandem with motions for summary judgment. The usual judicial reflex is to go ahead and adjudicate the Daubert issues as they pertain to summary judgment, but it is worth noting that no rule requires the district courts to do so. Respectable authority sanctions deferral of evidentiary decisions, including Daubert rulings, until trial. See, e.g., United States v. Nichols, 169 F.3d 1255, 1262-64 (10th Cir.), cert. denied, 528 U.S. 934 (1999).
When Daubert and Rule 56 motions are adjudicated together, the thing to watch for is colliding standards of review. Under the standards for summary judgment established in Fed. R. Civ. P. 56, the district court enjoys almost no discretion. Appellate review is de novo, and if the nonmoving party produces admissible evidence that would sustain a jury verdict in its favor on the point in dispute, the motion must be denied. On Daubert issues, by contrast, the district courts enjoy wider latitude, and appellate review is for abuse of discretion.
Of course, it is precisely this difference in standards of review that the use of Daubert motions in connection with summary judgment is intended to exploit. If the parties' differences can be portrayed as primarily a dispute over the reliability of plaintiff's expert evidence, the district court may enjoy significant leeway to resolve the controversy by excluding the evidence under Daubert -- such testimony then being unavailable to plaintiff for use in opposing summary judgment. Conversely, if the points of contention can be characterized as primarily a factual dispute between reliable experts, then summary judgment on those points should be unavailable.
Most often, courts and litigants do a reasonably good job of acknowledging this difference in standards of review, at least to the extent of reciting the applicable standards and purporting to apply them in textually separate Daubert and summary judgment analyses. One must nevertheless remain constantly on guard against confusion or conflation of the two analyses. One particularly gray area is "fit." Some Daubert decisions have treated "fit" as a more stringent variant of relevance. Under this (controversial) construction, a district court could potentially exclude, as wanting in "fit" under Daubert, even reliable evidence that concededly satisfies the liberal standards for relevance embodied in Fed. R. Evid. 401. Any such ruling should be greeted, when it comes, with howls of protest.
Tactics and Timing
If the Rule 56/Daubert motion package is served at a time before expert discovery is closed, the nonmoving party has two weapons in his or her arsenal that he or she would otherwise lack. First, the nonmoving party may be able to ward off summary judgment by means of a Rule 56(f) affidavit, giving reasons why the expert testimony necessary to oppose defendant's summary judgment motion will not be available until some later time.
Second, the nonmoving party's expert may be able, via supplementation, to modify his or her opinions to meet the movant's Daubert objection and/or to defeat the movant's summary judgment arguments. The reason that supplementation may be necessary for this purpose is that only evidence admissible at trial may be employed on a motion for summary judgment, and only expert opinions reflected in the expert's report (as supplemented from time to time) will be admissible at trial. Of course, once an affidavit offering a revised expert opinion is served with the nonmoving party's Daubert or summary judgment opposition, supplementation (if still timely) has been technically effected, whether the word "supplement" is used or not, because a writing reflecting the new testimony has been transmitted. It will often be safest, however, to call a supplemental opinion what it is, so as to avert pointless arguments over preclusive sanctions.
Formal supplementation, meanwhile, should not technically be required to defend the expert's methodologies. The expert's job, in the report, is to offer support for the reliability of what the expert did -- not to anticipate and refute every imaginable Daubert argument that it should have been done differently. If the rules required disclosure of all arguments that might be used to rebuff each possible attack on the disclosures, an infinite regress would threaten -- and only seers could be experts. All the same, as discussed elsewhere at this site, there is generally no harm in judicious use of supplementation, where it remains timely, to buttress the report in areas of methodological vulnerability.