United States v. Reddy, 2013 U.S. App. LEXIS 17018 (11th Cir. Aug. 16, 2013):

It is important to note, however, that "it is not the role of the district court to make ultimate conclusions as to the persuasiveness of the proffered evidence." Quiet Tech. DC--8, Inc. v. Hurel--Dubois UK Ltd., 326 F.3d 1333, 1341 (11th Cir. 2003). Instead, "[v]igorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence." Daubert, 509 U.S. at 596, 113 S. Ct. at 2798. For "in most cases, objections to the inadequacies of a study are more appropriately considered an objection going to the weight of the evidence rather than its admissibility." Hemmings v. Tidyman's Inc., 285 F.3d 1174, 1188 (9th Cir. 2002). See also Quiet Tech., 326 F.3d at 1346 (stating that, "[n]ormally, failure to include variables will affect the analysis' probativeness, not its admissibility").

Moreover, with respect to admissibility, we held in City of Tuscaloosa, that an expert's proffered opinion may be unpacked such that what is admissible under Daubert is permitted, and any portion that does not meet Daubert standards is not permitted. 158 F.3d 548, 564-65 (11th Cir. 1998). Therefore, when irrelevant data can "readily be separated from" that which is germane, the relevant portions can still be used by the proponent of the evidence. Id., at 567. The proponent of the evidence has the burden of establishing its admissibility by a preponderance of the evidence. See McCorvey v. Baxter Healthcare Corp., 298 F.3d 1253, 1256 (11th Cir. 2002).***

1. Qualifications

Pursuant to Rule 702, an expert witness includes persons qualified "by knowledge, skill, experience, training, or education." Fed. R. Evid. 702.

In this case, the district court precluded all of the proffered testimony from both Drs. Morrissey and Sacks. With respect to Dr. Morrissey, the court explained, "As the person who developed the statistical strategy to collect the sample for Dr. Sacks to review, Dr. Morrissey must qualify as an expert in statistics." The district court noted that Dr. Morrissey had "some knowledge of statistics" since "she studied statistics for nine months at Harvard and had exposure to statistics" in her prior work experience. Nevertheless, bothered that Dr. Morrissey had never used the RAT--STATS program before, and had never designed a peer review study, the district court ultimately found that Dr. Morrissey was not "an expert qualified to employ statistical techniques to develop the peer review procedure she developed here." In like fashion, the district court found that Dr. Sacks was "not qualified to testify that the group of images he selected to review was statistically accurate as a random selection of images." The district court was overly focused on what it deemed an unreliable sample selection process.

The district court's reliance on its finding that neither Dr. Morrissey nor Dr. Sacks possessed the requisite expertise in the field of statistics, is perplexing. Dr. Morrissey, admittedly not a master's level statistician, is a board-certified internist with a master's degree in public health from Harvard University. More importantly, Dr. Morrissey completed significant coursework in the area of statistics while at Harvard and had a wealth of prior experience, including working with statisticians as a peer reviewer. Questions concerning Dr. Morrissey's qualifications were for cross-examination. See, e.g., United States v. Valencia, 600 F.3d 389, 425-26 (5th Cir. 2010) (affirming trial court's admission of statistical study and noting that challenges to the study could be highlighted by opposing counsel on cross-examination). Similarly, it was not seriously disputed that Dr. Sacks was qualified to provide competent opinion testimony concerning his medical peer review. Dr. Sacks was a graduate of Cornell University, obtained his medical degree from UCLA, had completed a four-year residency in diagnostic radiology at Emory University, and was board-certified. In short, Dr. Sacks did not have to be trained in statistics to successfully conduct a peer review of RSI radiology reports.

Further, the authority relied upon by the Government for this proposition is inapposite. See, e.g., Johnson v. DeSoto Cty. Bd. of Comm'rs, 204 F.3d 1335, 1342, 1342 n.14 (11th Cir. 2000) (voting rights case ruling that statistical evidence derived from voter registration data is admissible under Daubert to determine relevant population features; noting that if voter registration figures are less reliable than other sources of population demographics, and that if proposed expert makes faulty assumptions, these go "to the weight of the evidence" and are "freely challengeable on cross-examination"). The purpose of the peer review study in the instant case was not to assist the jury in determining if a certain fact or inference was statistically likely, but rather, whether the consistent radiological findings of Dr. Sacks imply that it was more likely that Dr. Reddy in fact reviewed the images for which he attested. We conclude that these findings amount to clear error.