United States v. Mejia, 448 F.3d 436 (D.C. Cir. 2006).  Prosecution in narcotics trial offers testimony from law enforcement officer re drug jargon.  Jury convicts.  Admissibility affirmed.  Defendant complains that district court permitted officer's designation as expert based solely on officer's long experience in narcotics investigations.  That is true, but it was not error.

United States v. Miller, 395 F.3d 452 (D.C. Cir.), vacated on other grounds, 125 S. Ct. 2554 (2005).  Detective Tyrone Thomas testifies at drug trial that defendant's conduct is consistent with intent to distribute.  Jury convicts.  Admissibility affirmed.  Defendant did not object at trial and so review is for plain error.  Testimony was properly admitted under Fed. R. Evid. 702, as detective was testifying to matters not within common knowledge of average juror.  Defendant also argues that testimony was inadmissible expert evidence on mens rea under Fed. R. Evid. 704.  But although prosecutor's question did ask about "intent," detective's answer avoided that word and focused on modus operandi evidence.  Moreover, detective did make clear that he had no personal knowledge about defendant or facts of case.  That is enough, on plain error review, to avert reversal for abuse of discretion.

Gordon v. Pavot, No. 03-7182 (D.C. Cir. Jan. 4, 2005) (unpublished), cert. denied, 126 S. Ct. 265 (2005).  District court grants summary judgment to defendants [after excluding plaintiffs' expert testimony?].  Affirmed.  "The district court properly granted summary judgment on appellant's claims of medical malpractice and lack of informed consent because those claims were not supported by expert testimony, which was required to establish the elements of his case. See Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993)."

Edison Elec. Inst. v. Envtl. Protection Agency, 391 F.3d 1267 (D.C. Cir. 2004).  Various corporate and municipal dischargers of pollutants challenge EPA's promulgation of water testing methods for "whole effluent toxicity" or "WET" water quality standards, arguing that tests should be measured against Daubert, because they will later be used in enforcement proceedings in federal court.  Petition for review denied.  "Evidentiary rules govern the admissibility of evidence at trial, not the establishment of the processes whereby such evidence will be created."

Meister v. Med. Eng'g Corp., 267 F.3d 1123 (D.C. Cir. 2001).  Silicone breast-implant plaintiff with scleroderma offers treating physician and pathologist as causation experts.  Trial court initially denies defendants' Daubert motions but later grants defendants' motion for judgment as matter of law or new trial after jury returns verdict for plaintiff.  Exclusion affirmed.  Treating physician performed differential diagnosis, but case study reports were not sufficient to "rule in" silicone as potential cause of scleroderma in face of strong body of epidemiological research showing no causal nexus, and pathologist's causation opinion was tentative and insufficient; "chemical, in vitro, and in vivo ... studies ... singly or in combination, are not capable of proving causation in human beings in the face of the overwhelming body of contradictory epidemiological evidence."  Courts elsewhere are unanimous in rejecting similar causation evidence in silicone breast implant cases.

United States v. Williams, 212 F.3d 1305 (D.C. Cir.), cert. denied, 531 U.S. 1056 (2000).  Man fleeing police throws gun in river.  At man's trial for unlawful possession of handgun by felon, prosecution establishes that defendant is drug user.  Police officer then testifies for prosecution, on redirect, that in officer's experience, drug users and dealers commonly carry guns for protection.  District court overrules defendant's objection and refuses to permit recross examination.  Conviction affirmed (because admitting evidence was harmless error).  Officer testified that he had participated in only ten or eleven gun arrests, and no evidence of record suggests that those prior arrests involved drugs, so officer was not qualified to testify as expert.   Nor did prosecution lay sufficient foundation for officer's testimony to be admissible as lay opinion.  Trial courts do enjoy discretion in decisions whether to admit opinion testimony, but their discretion is predicated in part on assumption that cross examination will be permitted if weak testimony is admitted (citing Daubert), and no cross was permitted here.  However, error was harmless, because other evidence amply supported finding of guilt, and also because trial court gave suitable jury instructions.