Can An Expert Relay Hearsay Evidence To The Jury?

The California Supreme Court recently answered this question in People v. Sanchez, 63 Cal. 4th 665 (2016) as follows: No—not if the hearsay communicates case-specific facts. While an expert may assume the existence of case-specific facts to explain his or her opinion, the expert cannot relay such facts and treat them as true. Sanchez is important for trial lawyers because it restores the distinction between general background hearsay (which can be relayed to a jury) and case-specific hearsay (which cannot). As a matter of advocacy, Sanchez merely requires what skilled trial lawyers already do: present the most credible and persuasive evidence to the jury. 

The Law Pre- and Post-Sanchez, and its Implications in Civil Trials

To understand the implications of Sanchez, examining a case it expressly disapproves is instructive. In People v. Bell, 40 Cal. 4th 582, 608 (2007), the California Supreme Court examined the framework in which expert witnesses could relay inadmissible hearsay to a jury. The defendant in Bell was charged with murder, and a defense expert diagnosed him as having borderline personality disorder. Id. at 589. Among the materials relied on by the expert was an interview where the defendant described childhood abuse and his thoughts during the homicide. Id. at 607-08.  

The trial court sustained the prosecution's objection to "the psychologist 'reciting specific statements made by the defendant to him ... under the guise' of explaining the basis for his expert opinion." Id. The defense argued that "such statements were admissible, with a limiting instruction if necessary, under Evidence Code section 802 to show the basis for [the expert's] opinion." Id. at 608. The trial court ruled that the expert could testify about what the defendant said regarding his "psychological background," but he could not testify about what the defendant said about the events on the day of the crime. Id. 

The California Supreme Court affirmed. The Court explained how trial courts should consider hearsay evidence relied on by expert witnesses. Starting with Evidence Code section 801, "[e]xpert testimony may ... be premised on material that is not admitted into evidence so long as it is material of a type that is reasonably relied upon by experts in the particular field in forming their opinions." Cal. Evid. Code § 801(b). 

Next, Section 802 "allows an expert to 'state on direct examination the reasons for his opinion and the matter ... upon which it is based,' [accordingly] an expert witness whose opinion is based on such inadmissible matter can, when testifying, describe the material that forms the basis of the opinion." Bell, 40 Cal. 4th at 608, citing People v. Coleman, 38 Cal. 3d 69, 91 (1985). But while an expert can describe the material that forms the basis of the opinion, trial courts are afforded "considerable discretion" to prevent the jury from hearing "incompetent hearsay." Bell, 40 Cal. 4th at 608. With this backdrop, the Court articulated the following framework to consider the admission of expert-relied-on hearsay:

First, determine whether the hearsay is of a type that is reasonably relied upon by experts in the particular field in forming their opinions. Id. 

Second, if the hearsay is of a type that is reasonably relied upon by experts, the expert may describe the material that forms the basis of the opinion (subject to the court's discretion). Id. 

Third, the trial court has discretion to control the form in which the expert is questioned to prevent the jury hearing "incompetent hearsay." The trial court also has discretion to weigh the probative value of inadmissible evidence against the risk that the jury might improperly consider it as independent proof of certain facts. Id. 

With respect to the risks identified in step three, the Bell Court explained that, "[m]ost often, hearsay problems will be cured by an instruction that matters admitted through an expert go only to the basis of his opinion and should not be considered for their truth." Id., citing Coleman, 38 Cal. 3d at 92. And when a limiting instruction may not be enough, Evidence Code section 352 allows the court to exclude any hearsay matter whose irrelevance, unreliability, or potential for prejudice outweighs its probative value. Id. 

People v. Sanchez: Rejecting the Rationale that a Limiting Instruction Can Permit the Admission of Case-Specific Hearsay

Sanchez expressly disapproved the rationale of Bell and its progeny. 63 Cal. 4th at 686 n.13. Sanchez held that limiting instructions were insufficient cures. Id. at 687. The Sanchez Court reasoned that when an expert relies on case-specific hearsay to form an opinion, the validity of the opinion ultimately turns on the truth of such hearsay. See id. at 682-83. And if the opinion turns on the truth of the hearsay, it is illogical to tell the jury the hearsay should only be considered for the expert's "basis," but not its "truth"—because for the opinion to have an adequate "basis," the facts need to be "true." See id. at 684. 

The facts of Sanchez begin with two Santa Ana police officers making eye contact with defendant Sanchez. Sanchez then ran upstairs into an apartment—which was not his—where the police entered and arrested him. Id. at 671. A loaded gun and a plastic baggie with heroin and methamphetamine inside (all packaged for sale) were found on a tarp several feet below the bathroom window. Id. Sanchez was charged with possession of a firearm by a felon, possession of drugs while armed with a loaded firearm, as well as crimes related to gang activity. Specifically, he was charged with active participation in the “Delhi” street gang and the commission of a felony for the benefit of the Delhi gang. Id.   

The prosecution called a gang expert, David Stow, to testify. Id. Stow testified about the Santa Ana Police Department’s effort to control gang activity by issuing “STEP notices” to people associating with known gang members. Id. at 672. These STEP notices inform the recipient that he is associating with a known gang, that the gang engages in criminal activity, and that if the recipient commits certain crimes with gang members, he faces increased penalties. Id. 

Stow also discussed the specifics of the STEP notice issued to Sanchez. Id. He explained that Sanchez told the issuing officer that he had been “kicking it” (i.e., “hanging out and associating”) with Delhi gang members. Id. Stow also discussed four other police accounts—from his review of police records—identifying Sanchez’s association with the Delhi gang. Id. Based on statements found in these records that Stow reviewed, Stow opined that Sanchez was indeed a member of the Delhi gang. Id. 

After he was convicted as charged, Sanchez appealed. Sanchez argued that Stow introduced testimonial hearsay in violation of the Sixth Amendment’s Confrontation Clause. Id. at 679, citing U.S. Const., 6th Amend. (“In all criminal prosecutions, the accused shall enjoy the right … to be confronted with the witnesses against him.”). The California Supreme Court examined the appeal by addressing two questions: First, whether Stow’s description of Sanchez’s past contacts with police were admitted for their truth; if not, the statements were not hearsay (and the inquiry would end). Second, if the statements were offered for their truth (and thus were hearsay), whether the statements constituted testimonial hearsay. Id. at 674.

Turning to the first question, the Court examined the traditional distinction between general background hearsay and case-specific hearsay. With respect to the former, expert witnesses had historically been permitted to relay information acquired through training and experience, even though that information comes from hearsay—e.g., conversations with others, lectures, study of learned treatises, etc. Id. at 675. The Court explained how this rule emerged from pragmatism: “A physician is not required to personally replicate all medical experiments dating back to the time of Galen in order to relate generally accepted medical knowledge that will assist the jury in deciding the case at hand.” Id. Accordingly, “the common law accepted that an expert’s general knowledge often came from inadmissible evidence.” Id., at 676, citing Volek, Federal Rule of Evidence 703: The Back Door and the Confrontation Clause, Ten Years Later, 80 Fordham L. Rev. 959, 965 (2011). 

But unlike general background knowledge, expert witnesses had traditionally been precluded from introducing case-specific hearsay about which the expert had no personal knowledge. Id. at 676. An expert was permitted to assume a certain set of case-specific facts and discuss their meaning or significance, but the expert could not introduce those case-specific facts in evidence. To help understand this distinction between general background and case-specific facts, the Court provided four examples:

Car Accident Case: An expert witness could not introduce the case-specific fact that there were fifteen feet of skid marks found at the scene; that needs be introduced through someone who, for example, measured the skid marks. An expert could testify about how skid marks are left on pavement, that skid marks can be used to estimate the speed of a vehicle, and that the car was—assuming a fifteen-foot skid mark—traveling at eighty miles per hour. Id. at 677.

Homicide Case: An expert witness could not introduce case-specific information that hemorrhaging in eyes was noted during a victim's autopsy. That needs to be established by the autopsy surgeon or another witnesses—including a witness authenticating a photograph depicting it. The expert witness could testify about what conclusions can be drawn from hemorrhaging eyes. Id.  

Gang Association Case: In a case where the prosecution wished to prove that a tattoo on the defendant’s arm was evidence of gang-membership, the existence of the tattoo on the defendant’s arm is a case-specific fact that would need to be established through an eye witness or authenticated photograph. The prosecution's expert witness could then testify that the symbol depicted was adopted by a certain street gang. The expert could also opine that the presence of the tattoo on the defendant indicated he was a member of that gang. Id.

Personal Injury Case: In a case where the plaintiff allegedly suffered a head injury, the case-specific fact that the plaintiff suffered an earlier head injury as a child would need to be established by an eye witness, treating physician, or diagnostic medical records. The expert witness could then opine on the prior injury’s long-term effects. Id.

With the passage of the Evidence Code in 1965, the distinction between general background facts and case-specific facts eroded. Id. at 678. Specifically, Evidence Code section 801, subdivision (b) provides that an expert may render an opinion “[b]ased on matter … made known to him at or before the hearing, whether or not admissible, that is of a type that reasonably may be relied upon by an expert in forming an opinion upon the subject to which his testimony relates, unless an expert is precluded by law from using such matter as a basis for his opinion.” (Emphasis added).

Thus, with the passage of Section 801, experts were permitted to identify the “matter” relied on in forming opinions. But when the matter relied on included hearsay, questions remained regarding (1) how much substantive detail the expert could provide (i.e., how much hearsay could be introduced), and (2) how could the jury consider the evidence in evaluating the expert’s opinion. Id. What became a common practice was trial courts instructing jurors that any case-specific hearsay introduced by the expert should be considered in evaluating the basis of his opinion, but should not be considered for their truth. Id., citing People v. Montiel, 5 Cal. 4th 877, 919 (1993).

The Sanchez Court, however, concluded that providing jurors with an instruction to disregard such evidence for its truth was “no longer tenable because an expert’s testimony regarding the basis for an opinion must be considered for its truth by the jury.” Id. at 679 (emphasis in original). The reason is because when an expert relies on hearsay to provide case-specific facts to form his opinion, the validity of the expert’s opinion ultimately turns on the truth of such facts. Id. at 682, citing Williams v. Illinois, 567 U.S. 50, __ (2012). 

Accordingly, the Court adopted the following rule: “When any expert relates to the jury case-specific out-of-court statements, and treats the content of those statements as true and accurate to support the expert’s opinion, the statements are hearsay. Id. at 686. The Court expressly disapproved prior decisions that concluded that an expert’s basis testimony is not offered for its truth, or that a limiting instruction (coupled with an evaluation of the potential prejudicial impact under Evidence Code section 352) sufficiently addressed any hearsay concerns. Id. at 686 n.13.

Because Sanchez was a criminal case, the Court considered the second question: whether the hearsay introduced by Stow was testimonial hearsay. Id. at 687-98. "Testimonial hearsay” is a term of art that has received various definitions and formulations. In Crawford v. Washington, 541 U.S. 36, 68 (2004), the Supreme Court stated that it, “applies at a minimum to prior testimony at a preliminary hearing, before a grand jury, or at a former trial; and to police interrogations. These are the modern practices with [the] closest kinship to the abuses at which the Confrontation Clause was directed.”

As this Crawford doctrine evolved, the Supreme Court concluded that not all statements made during police questioning constituted testimonial hearsay. Sanchez, 63 Cal. 4th at 687, citing Davis v. Washington, 547 U.S. 813 (2006). A test was created in Davis: “Statements are nontestimonial when made in the course of police interrogation under circumstances objectively indicating that the primary purpose of the interrogation is to enable police assistance to meet an ongoing emergency. They are testimonial when the circumstances objectively indicate that there is no such ongoing emergency, and that the primary purpose of the interrogation is to establish or prove past events potentially relevant to later criminal prosecution.” 547 U.S. at 822 (emphasis added).

The Crawford doctrine was extended in Melendez-Diaz v. Massachusetts, 557 U.S. 305 (2009) to scientific test results. In Melendez-Diaz, crime lab analysts prepared documents certifying that a sample of material recovered from the defendant was tested and determined to contain an illegal drug. Certificates were sworn before a notary public and admitted at trial in lieu of the analyst’s testimony. Id. at 308. The Court explained that the certificates were “functionally identical to live, in-court testimony, doing ‘precisely what a witness does on direct examination.’” Id. at 310 – 311. Thus, “[u]nder our decision in Crawford the analysts’ affidavits were testimonial statements, and the analysts were ‘witnesses’ for the purposes of the Sixth Amendment.” Id. at 311.  

Turning to the reports in Sanchez, the California Supreme Court ruled that the reports relied on by Stow were compiled during police investigations of complicated crimes. Sanchez, 63 Cal. 4th at 694. Accordingly, “Crawfordteaches those hearsay statements are generally testimonial unless they are made in the context of an ongoing emergency … or for some primary purpose other than preserving facts for use at trial.” Id.

The same conclusion was held with respect to the STEP notices: “[T]he portion of the STEP notice relied upon by Stow was that part retained by police. That portion recorded defendant’s biographical information, whom he was with, and what statements he made. It cannot be said that defendant’s primary purpose in making the statements was to establish facts to be later used again him or his companions at trial.” Id. at 696 (emphasis in original). So while the admission of hearsay can sometimes be a mere statutory law error (i.e., the admission of hearsay evidence), the admission of testimonial hearsay violated Sanchez’s confrontation rights. And because the error was not harmless beyond a reasonable doubt, the case was remanded. Id. at 699.  

Post-Sanchez: Applying Sanchez in the Context of Cross-Examining an Opposing Expert

But what about the flipside of People v. Sanchez? In October 2017, California’s Third District considered this issue in People v. Malik, 16 Cal. App. 5th 587 (2017). Malik involved a defendant convicted of assault with a deadly weapon and making a criminal threat. Id. at 437. At trial, the defendant sought to establish that he acted in self-defense, and that he suffered from PTSD from his prior military service in the Iraq War. Id. at 439. His counsel called Dr. Linda Barnard as an expert in PTSD. Id. Dr. Barnard reviewed various police reports and interviews with defendant and his parents, and formed the opinion that the defendant suffered from PTSD stemming from his experiences in the war and a prior shooting experience. Id.

On cross-examination, the prosecutor was allowed—over defense counsel’s objections—to to ask about various police and sheriff reports from multiple jurisdictions generated between 2001 and 2013. Id. at 440. The prosecutor described the contents of these reports, which included instances where the defendant (1) kicked out a window at a gas station and choked the station attendant, (2) threatened his wife with a gun, threw her to the ground, and then had a standoff with police officers, and (3) screamed at a bar, punched a manager in the face, and ran from police while screaming profanities. Id., at 441 - 42. After introducing these contents, the prosecutor then asked whether Dr. Barnard had “taken the purported facts contained therein into consideration in forming her conclusions.” Id.  

On appeal, the defendant argued that the trial court abused its discretion and violated his federal constitutional rights by allowing the prosecutor to cross-examine Dr. Barnard about her review of several police reports. Id. Specifically, the defendant argued that “the prosecutor related ‘irrelevant and prejudicial hearsay’ to the jury through her questioning of the expert in violation of his due process rights.” Id.

The Court acknowledged the line drawn in Sanchez between “case-specific testimonial hearsay” and “generally accepted background information.” See id. at 443. The Court also noted the distinction between Sanchez and the issue presented in Malik: “Here, we do not have a situation in which a prosecution expert related case-specific hearsay to the jury and treated those hearsay statements as true to support her opinion. Instead, the prosecutor related case-specific hearsay, through cross-examination of the defense expert, and asked whether she considered that information in forming her conclusion [that] defendant suffered from PTSD.” Id. (emphasis in original). And while the Court acknowledged that this was arguably the “flipside” of Sanchez, it found “no authority … for the proposition that the breadth of permissible cross-examination extends to the admission of case-specific testimonial hearsay in violation of a defendant’s right of confrontation.” Id. Accordingly, the Court held that “the reasoning of Sanchez applies equally in these circumstances.” Id. at 444. 

For guidance on how to examine experts (on direct and cross), please read the The Art: Examining Expert Witnesses in the Post-Sanchez Era.