United States v. Diaz - Ninth Circuit

Headline: Ninth Circuit panel holds medical expert’s testimony did not constitute a legal conclusion in violation of Federal Rules of Evidence 702 and 704 but rather provided the jury with professional opinions regarding the standard of care in the medical community.

Areas of Law: Evidence; Expert Witness Testimony

Issues Presented: Whether a medical expert’s opinions that a physician prescribed controlled substances outside the usual course of medical practice and without a legitimate purpose were legal conclusions in violation of Federal Rules of Evidence 702 and 704.

Brief Summary: The Ninth Circuit panel held that terms used by an expert witness did not have a specialized meaning in the law and were not an attempt to instruct the jury on the law or on how to apply the law to the facts of the case.  Therefore, his testimony was not an impermissible legal conclusion.

Significance: This case clarifies that expert testimony is to be admitted so long as the expert does not substitute her or his judgment for the jury’s.  Where a term does not have a separate, distinct and specialized meaning in the law, an expert can resort to the language in a statute when rendering an opinion.

Extended Summary: Dr. Julio Diaz (“Diaz”) operated a clinic in Santa Barbara, California, where he offered pain management and treatment.  Between 2008 and 2011, he wrote more than 50,000 prescriptions and prescribed more than 5 million opiate pills.  The government indicted Diaz for multiple counts of distributing controlled prescription drugs in violation of 21 U.S.C. § 841(a)(1).

To prevail at trial, the government had to prove: (1) that the practitioner distributed controlled substances, (2) that the distribution of those controlled substances was outside the usual course of professional practice and without a legitimate medical purpose, and (3) that the practitioner acted with the intent to distribute the drugs and with intent to distribute them outside the course of professional practice. United States v. Feingold, 454 F.3d 1001, 1008 (9th Cir. 2006) (emphasis omitted).

At trial, the government’s expert witness, Dr. Rick Chavez (“Chavez”), testified without objection that Diaz’s prescriptions were written “outside the usual course of medical practice” and “without a legitimate purpose.” The jury convicted Diaz on all counts.  Diaz appealed on the grounds that the admission of the expert’s testimony was plain error.

The Ninth Circuit panel affirmed the conviction.  It began its opinion with a discussion of the Federal Rules of Evidence (“FRE”) and earlier court precedenst on the admissibility of expert testimony.  FRE 702(a) requires that expert testimony “help the trier of fact to understand the evidence or to determine a fact in issue.”  FRE 704(a) clarifies that “[a]n opinion is not objectionable just because it embraces an ultimate issue.” After the adoption of Rule 704, the Ninth Circuit held that the common law posed no barrier to testimony by a physician “that the appellant was not prescribing drugs in the usual course of a professional practice and for a legitimate medical purpose.” United States v. Davis, 564 F.2d 840, 845 (9th Cir. 1977), cert denied, 434 U.S. 1015 (1978). However, “an expert witness cannot give an opinion as to her legal conclusion, i.e., an opinion on an ultimate issue of law.” Hangarter v. Provident Life & Accident Ins. Co., 373 F.3d 998, 1016 (9th Cir. 2004) (emphasis in original).

Diaz argued that Chavez impermissibly testified about whether Diaz distributed controlled substances outside the course of professional practice. The prosecutor drew Chavez’s attention to prescriptions that Diaz wrote for particular patients and asked whether the “prescriptions were issued outside the usual course of medical practice” and whether “the drugs [were] given to [the patients] for a legitimate medical purpose.” Chavez answered “yes” to the first question, and “no” to the second. Diaz argued that the prosecutor’s questions used the language in § 841(a)(1); therefore, the responses by Chavez substituted his judgment for the jury’s.

Both Diaz and the government relied on the Ninth Circuit’s decision in United States v. Moran, which held that an expert witness’s opinion that a transaction was a “sham” was admissible when, under the judge’s instructions, even if the transactions were a sham, the jury would still have to draw its own inference from that predicate testimony to answer the ultimate fact question of whether income tax was owed.  493 F.3d 1002, 1008 (9th Cir. 2007).

Diaz contended this holding means that when an expert witness opinion encompasses the entirety of an element of a crime, it reaches “an ultimate issue of law” and therefore is inadmissible. The government understood Moran to mean that an expert witness may not offer an opinion on the defendant’s guilt or innocence. The Ninth Circuit panel found the holding in Moran to be too narrow to determine the issue in this case.

The Ninth Circuit panel then looked to decisions of other circuits.  The Fourth Circuit held that the district court did not plainly err by allowing the jury to consider expert opinion testimony that a defendant’s treatment of his patients was “outside the usual course of medical practice.” United States v. McIver, 470 F.3d 550, 561-62 (4th Cir. 2006). The Fourth Circuit reasoned that the phrase “outside the usual course of medical practice” was not so specialized as to render the expert opinion testimony inadmissible because there are only so many ways of conveying the impression of a physician abandoning his professional role. Id. at 560-562.  Likewise, the Sixth Circuit held in United States v. Volkam that the district court did not abuse its discretion by overruling an objection that a physician defendant’s prescriptions “were not written for any legitimate medical purpose.” 797 F.3d 377, 388-389 (6th Cir. 2015). The Sixth Circuit came to this reasoning on the same grounds as the Fourth Circuit.

The Ninth Circuit panel found these cases persuasive and on point. It reasoned that Chavez’s testimony was helpful because a lay jury would not have the requisite knowledge to evaluate whether the dosage, mix, and course of narcotics prescribed by Diaz were medically appropriate for the conditions alleged in the complaint. Although the phrases Chaves used appear in § 841(a)(1), these phrases were used in their ordinary, everyday sense and did not have a separate, distinct, and specialized legal significance.

For these reasons, Chavez expert testimony did not violate FRE 702 and 704, and the district court did not plainly err by admitting the expert testimony into evidence.


To read the full opinion, please visit:


Panel: Andrew J. Kleinfeld, Susan P. Graber, and Morgan Christen, Circuit Judges

Argument Date: October 6, 2017

Date of Opinion: December 6, 2017

Docket Number: No. 15-50538

Decided: Affirmed.

Case Alert Author: Blaine Brown

Counsel: Davina T. Chen (argued), Glendale, California, for Defendant-Appellant; Ann Luotto Wolf (argued), Assistant United States Attorney; Dennise D. Willett, Chief, Santa Ana Branch Office; United States Attorney’s Office, Los Angeles, California; for Plaintiff-Appellee.

Author of Opinion:  Circuit Judge Christen

Circuit: Ninth Circuit

Case Alert Supervisor: Philip L. Merkel

Leave a Reply