Second Look: Avoiding An "Inappropriately Rigid Daubert Standard"

In drug conspiracy trial, exclusion of defense medical expert testimony regarding the defendant's susceptibility to entrapment was erroneous under FRE 702 because it was based on an "inapppropriately rigid Daubert standard" of scientific validity rather than "specialized knowledge" which is evaluated based on what "a good [physician] would [consider] in determining what is reliable knowledge in the profession" of medicine, in United States v. Sandoval-Mendoza, 472 F.3d 645 (9th Cir. Dec. 27, 2006) (No. 04-10118)

Need For A Second Look?

In the blog article Ninth Circuit's Per Se Rule That “Any Overnight Ban On Communication” Of Defendant With Counsel Violates Sixth Amendment (August 12, 2010), we noted that besides reversing the defendant's conviction for violations of his Sixth Amendment rights, the circuit also identified an error in excluding medical expert testimony pertinent to a claimed defense in the case. Today's blog essay examines the inroads this case, United States v. Sandoval-Mendoza had in analysis of FRE 702 and application of the Daubert standard to trial court gate keeping of expert testimony.

Expert Medical Proof Of Entrapment Necessary

In the case, defendant Eduardo Sandoval-Mendoza and his twin brother Ricardo were prosecuted for conspiring to distribute methamphetamine. The defendant admitted selling methamphetamine at trial, but claimed that he was entrapped by government informants who recorded conversations of the drug transactions, knowing that the defendant suffered from effects of a brain tumor and as a result was “especially susceptible to suggestion.” They took advantage of this, “preyed upon his weakness,” and managed to make the encounter seem a drug sale. Sandoval-Mendoza, 472 F.3d at 647.

During the trial, the defense sought to lay a basis of the defense of entrapment. It sought to introduce expert testimony by a neurologist and neuropsychologist explaining that the defendant had a large brain tumor which had damaged his intelligence, memory, and his judgment. This condition made the defendant particularly susceptible to suggestion. The district court decided to exclude this evidence after a Daubert hearing, finding that the expert testimony “lack[ed] ... scientific validity.” There was no disagreement that the defendant had a tumor. The "only disagreement" among the experts "was whether it caused susceptibility to inducement." The court excluded the defense experts regarding this because it believed that to be admissible the experts' testimony had to "make a causal connection” between the tumor and the alleged inducement or predisposition of the defendant. Sandoval-Mendoza, 472 F.3d at 656.

Issue For Jury

The defendant was convicted and in his appeal raised as a ground the trial court's exclusion of the defendant's medical expert testimony. This exclusion hindered the defendant's defense that a brain tumor rendered him very susceptible to entrapment. The circuit noted that the issue of whether the defendant's brain condition affected his cognitive functioning was an issue to be resolved by the jury. While the defendant's expert evidence was not definitive, the experts did opine that the tumor and its resulting damage to the brain affected the defendant's judgment, which was confirmed by tests that "suggested a very low level of intellectual function" on the part of the defendant. The circuit found merit in the defendant's argument and reversed the defendant's conviction. Sandoval-Mendoza, 472 F.3d at 653.

According to the circuit, the trial court's exclusion of expert medical opinion testimony effectively "hid[]" from the jury the real issue to be determined at trial. This was "whether the government's informants induced a vulnerable and suggestible man to break the law. The informants did not testify, so the jury could not evaluate the pressure they put on Sandoval–Mendoza." In essence, this deprived the defendant of the right to make a defense since "[a]ll the jury had" was proof that the defendant "sold drugs, wiretap recordings in which he sounded like an experienced drug dealer, and a couple of lay witnesses testifying that he was addled by a brain tumor." This limited evidence regime left the defendant without the ability to "present his case to the jury." Sandoval-Mendoza, 472 F.3d at 657.

Too Rigid Application Of Daubert?

The circuit explained that the trial court had erred by using a Daubert standard that was too "rigid" as it applied to scientific knowledge. There was a more relaxed Daubert standard applicable to specialized or technical expert opinion, such as medical opinion. According to the circuit:

When evaluating specialized or technical expert opinion testimony, “the relevant reliability concerns may focus upon personal knowledge or experience.” Because medical expert opinion testimony “is based on specialized as distinguished from scientific knowledge, the Daubert factors are not intended to be exhaustive or unduly restrictive.” Under our decision in Sullivan v. United States Dep't of the Navy, the district court “applied an inappropriately rigid Daubert standard to medical expert testimony” by not accepting what “a good [physician] would in determining what is reliable knowledge in the [medical] profession.” A trial court should admit medical expert testimony if physicians would accept it as useful and reliable. Utility to the jury of medical expert testimony should be determined by what physicians would accept as useful.

The district court concluded that the proposed medical expert opinion testimony was unreliable because it did not conclusively prove Sandoval–Mendoza's brain tumor caused susceptibility to inducement or a lack of predisposition. But medical knowledge is often uncertain. The human body is complex, etiology is often uncertain, and ethical concerns often prevent double-blind studies calculated to establish statistical proof. This does not preclude the introduction of medical expert opinion testimony when medical knowledge “permits the assertion of a reasonable opinion.”
Sandoval-Mendoza, 472 F.3d at 655 (quoting Kumho Tire Co. v. Carmichael, 526 U.S. 137, 150 (1999), citing Sullivan v. U.S. Dep't of the Navy, 365 F.3d 827, 833-34 (9th Cir. 2004); United States v. Finley, 301 F.3d 1000, 1007 (9th Cir. 2002) (citation omitted)).


Applying the modified Daubert standard in the defendant's case readily led to a conclusion that the defense medical experts should not have been excluded. The circuit noted that the defendant's "experts were well qualified and had sufficient expertise in the neurology of brain tumors ." In addition, the circuit found that a sufficient foundation had been laid to show elements of the entrapment defense.


Federal Rules of Evidence