California Medical Expert Witness Directory

California has its own set of evidentiary rules and case law that govern the use of expert witnesses. As you plan for and work with a medical expert in a California case, keep in mind these California-specific legal standards which affect expert qualifications, admissibility of their testimony, and how their opinions are evaluated:

• Qualification of Experts (Evidence Code §720): California law sets a broad but important threshold for who may testify as an expert. Under Evidence Code §720(a), a person is qualified as an expert witness if they have “special knowledge, skill, experience, training, or education” sufficient to qualify them on the subject of their testimony. If the opposing party objects, the burden is on the proponent to show the expert’s qualifications before the expert can give an opinion. In practical terms, this means at trial (or even at deposition) you may need to lay a foundation for your expert’s expertise in the specific field. For example, to have a doctor testify about neurosurgery, you would establish their medical degree, residency/fellowship in neurosurgery, board certification, years of practice, etc., to satisfy §720. Usually, courts interpret §720 liberally, but they will exclude or limit an expert who strays outside their field of expertise. Additionally, §720(b) allows the expert’s qualifications to be shown by any admissible evidence, including the expert’s own testimony about their background. Tip: When hiring the expert, ensure their CV and background align tightly with the subject matter of the case so that you can easily clear this qualification hurdle. In medical malpractice cases, this means the expert ideally should practice or have practiced in the same specialty as the defendant – it strengthens the §720 foundation that they have the special knowledge “on the subject” at issue.
  
  

• Scope of Expert Opinion (Evidence Code §801): Section 801 of the Evidence Code governs what an expert can testify about. There are two key parts: §801(a) says the expert’s opinion must relate to a subject that is “sufficiently beyond common experience that the opinion of the expert would assist the trier of fact”. This codifies the idea that expert testimony should be helpful and on topics jurors can’t figure out for themselves. In a medical case, virtually all standard of care and causation issues meet this criterion, since laypersons generally don’t know what a competent doctor should do in a complex scenario or how a certain medical error could cause an injury. The second part, §801(b), requires that the expert’s opinion be based on matter (including facts, data, or even hearsay information) “that is of a type that reasonably may be relied upon by an expert in forming an opinion upon the subject.” In plain terms, the expert can rely on information that experts in that field normally use, even if that information might not be independently admissible in evidence. For example, a medical expert can rely on hospital records, lab results, or scientific studies – even though those might be hearsay – because medical professionals normally rely on such information. California allows this somewhat liberally: doctors rely on nurses’ notes, test results, consultations with colleagues, medical literature, etc. As long as it’s the kind of material that medical experts reasonably rely on, §801(b) permits the expert to base an opinion on it. However, the expert cannot act as a mere conduit for inadmissible evidence; they must use it to form their opinion, not just repeat it. Also note, if an expert is going to relate case-specific hearsay to the jury (for example, something a nurse told them), there have been evolving court decisions (like People v. Sanchez for criminal cases) requiring that the hearsay be independently admissible unless it’s general background information. In civil cases, the distinction can be nuanced. The safe practice is to have your expert rely on hearsay only as needed and be prepared to show it’s of a type experts rely on. In summary, §801 ensures experts stick to helpful subjects beyond lay knowledge and that their opinions have a reliable basis in the kind of data experts find trustworthy.
  
  

• Basis for Opinion and Disclosure (Evidence Code §802): California Evidence Code §802 allows an expert to explain the reasons for their opinion and the matter (information) on which it is based. A court may, however, require that the expert be examined on the underlying information before stating the opinion (this is sometimes done when there’s a question of admissibility). Essentially, §802 gives the expert latitude to discuss the foundational facts or data. However, if some of those facts are inadmissible (like hearsay statements), the court has discretion to limit how much of that gets disclosed to the jury, to avoid undue prejudice. This is sometimes a balancing act: you want the jury to hear enough of what the expert considered to judge the soundness of the opinion, but you must be careful not to elicit extensive hearsay from the expert. California judges often instruct the jury that certain information an expert relied on (like hearsay) is not to be considered for its truth, only to evaluate the opinion. It’s a fine line to walk. The key takeaway for working with your expert is: make sure they know they might have to lay out their reasoning and sources in detail, and nothing should come as a surprise. They should not rely on any secret sauce that isn’t revealed, because under §802, on cross-exam the opposing attorney can force them to disclose what exactly they relied upon. The expert should be ready to defend why each piece of information was pertinent and reliable in forming their conclusion.
  
  

• Cross-Examination of Experts (Evidence Code §721): Section 721 of the Evidence Code deals specifically with how experts can be cross-examined. §721(a) reiterates that an expert may be cross-examined “to the same extent as any other witness” and, in addition, fully cross-examined as to (1) their qualifications, (2) the subject matter of their testimony, and (3) the matter upon which their opinion is based and the reasons for their opinion. In practice, this means opposing counsel has wide latitude to probe your expert’s background (education, experience, potential biases), to question their understanding of the field, and to dig into every assumption, fact, or methodology underlying their opinion. Importantly, §721(b) addresses the use of publications on cross-exam. It provides that an expert who has given an opinion cannot be cross-examined about the content of any scientific or professional publication unless one of three conditions is met: (1) the expert referred to, considered, or relied on that publication in forming their opinion; (2) the publication has been admitted into evidence; or (3) the publication has been established as a reliable authority by the expert’s admission, another expert’s testimony, or judicial notice. If one of those conditions is satisfied, then relevant portions of the publication can be read into evidence (but not received as exhibits). What this means for you: Opposing counsel can’t just whip out some random textbook to contradict your expert unless they first get it deemed a reliable authority or get your expert to acknowledge it. Often, an opposing attorney will ask your expert in depo or trial, “Are you familiar with Such-and-Such textbook? Do you consider it authoritative?” If your expert says yes, then passages from that book can be used. If your expert says no, the attorney may try to have their own expert establish it as authoritative or ask the judge to take judicial notice. This is California’s approach to the learned treatise rule. Be sure to prepare your expert on how to handle questions about texts or articles. They should only endorse as authoritative those works they truly trust, and if confronted with a quotation, they should ask to see the full context. Section 721(b) prevents surprise attacks from obscure literature unless properly vetted, but a savvy cross-examiner will try to meet those conditions. Additionally, as a matter of strategy, you might use this too: if the defense expert relies on a particular medical article, you can cross-examine them on other parts of that article or other works if you get them admitted or acknowledged as reliable.
  
  

• Expert’s Compensation and Bias (Evidence Code §722): California explicitly allows inquiry into an expert’s compensation. Evidence Code §722(b) states that the compensation and expenses paid to an expert by the employing party is a proper subject of inquiry and may be considered relevant to the expert’s credibility. This means the jury can hear how much you are paying your expert (and likewise how much the other side is paying theirs). The idea is that a large payment could show potential bias or incentive to testify favorably. In practical terms, expect that at trial your expert will be asked, “Doctor, what is your hourly rate and how much have you billed so far in this case?” Prepare your expert to answer truthfully and matter-of-factly – it’s not something to be ashamed of. Many experts will say something like, “My rate is $500 per hour; I’ve spent about 30 hours so far.” That’s $15,000 – opposing counsel might then emphasize that amount to imply bias. In California, you cannot object to that question – it’s clearly allowed by §722. Some jurors might indeed think an expert is just saying what you want because they’re paid a lot. To mitigate this, some attorneys address it on direct: they bring out the expert’s rate themselves and ask if the expert’s opinion would change depending on who hires them (the expert of course says no, my opinions are the same regardless of who retains me). Since it’s coming in anyway, sometimes it’s better for the jury to hear it first from you in a neutral tone. Also, if your expert has done work mostly for one side (plaintiffs or defense), be ready for cross on that as potential bias. While §722(a) also notes that if the court appointed the expert, the appointment can be revealed (which is less common in civil med mal cases), typically it’s the payment that’s explored. The takeaway: be transparent with your expert’s fees and prepare for the optics of their compensation. By law, the jury gets to factor it into how much weight to give the testimony.
  
  

• Limitation on Number of Experts (Evidence Code §723): Section 723 gives the trial court the power to limit the number of expert witnesses that may be called by any party. This is to prevent cumulative, time-wasting testimony. In a California medical case, this could come into play if, say, a plaintiff names five different medical experts all opining on the same exact issue. A judge might use §723 to restrict that to one or two to avoid overkill. In most med mal cases, each side has one expert per specialty issue (one standard-of-care expert, maybe one causation expert if it’s a different field, etc.). Just be aware: you don’t want to line up more experts than you reasonably need on a given point, or the judge might step in. If you think you need multiple experts, differentiate their roles clearly (e.g., one cardiologist on standard of care, one neurologist on a different aspect of causation). California judges usually only invoke this rule if things seem truly redundant or if a party didn’t comply with the pretrial disclosure (you can’t suddenly decide to call three surprise experts at trial on the same issue). To be safe, comply with disclosure rules and be prepared to justify why each expert is necessary.
  
  

• The Sargon Standard (CA’s Approach to Expert Reliability): A major California Supreme Court case, Sargon Enterprises, Inc. v. University of Southern California (2012) 55 Cal.4th 747, has shaped how courts act as gatekeepers for expert testimony. In Sargon, the Court affirmed that trial judges have a duty to exclude speculative or unreliable expert opinions that lack a reasonable foundation. California is not a Daubert (federal standard) state per se, but Sargon essentially requires judges to ensure the expert’s reasoning and methodology are sound and that the opinion is not connected to the data only by the expert’s unfounded speculation. Sargon doesn’t demand a full-blown Daubert hearing in every case, but if one party challenges an expert’s opinion as too attenuated or speculative, the court will hold a hearing (often a motion in limine) to evaluate it. For medical experts in malpractice or injury cases, Sargon issues might arise if an expert is venturing into novel scientific theories or drawing big causation conclusions from limited facts. For example, if an expert were to say “this patient would have had a 100% recovery but for a one-hour delay in treatment” with little scientific support, that might be attacked as speculative. Under Sargon, judges will exclude opinions that lack a reliable basis or are based on leaps of logic or assumptions the expert can’t back up. The Sargon decision reiterated long-standing law that “under existing law, irrelevant or speculative matters are not a proper basis for an expert’s opinion”. For attorneys, the lesson is: make sure your expert’s opinions are well-grounded in the facts and science. If there’s a potential Sargon challenge, prepare your expert to defend the methodology (for instance, referencing medical studies, explaining step-by-step how they reached the conclusion). Conversely, you might use Sargon to attempt to exclude the other side’s expert if they are espousing a theory that is really dubious or not generally accepted. Note that California still adheres to the older Kelly/Frye rule for novel scientific techniques (requiring general acceptance in the scientific community), which is mostly applied in criminal cases (like forensic tests). In civil med mal, you usually won’t have a Kelly hearing unless someone is trying to use a brand-new, unaccepted diagnostic technique. But Sargon covers the broader realm of any expert reasoning. Always ask yourself: if challenged, can my expert show their opinion is the product of a reliable methodology and not just ipse dixit (“because I say so”)? If yes, you should be on solid footing.
  
  

• MICRA Considerations: The Medical Injury Compensation Reform Act (MICRA) is a set of California laws impacting medical malpractice cases. While MICRA is more about damages and procedure than evidence, it does have practical effects on expert witness considerations. The most well-known MICRA provision is the cap on non-economic damages (pain and suffering) in med mal cases. For decades this cap was $250,000, and many attorneys calibrated their spending on experts with that limit in mind (e.g., you wouldn’t hire multiple extremely expensive experts if the most your client could recover in general damages was $250k). As of 2023, California has updated the cap – it’s now $350,000 for non-death cases and $500,000 for wrongful death cases, with incremental increases over the next decade. This cap means that no matter how compelling your expert is about the patient’s suffering or long-term pain (which would be non-economic damage), the recovery is limited. Consequently, one strategic consideration is focusing your expert on areas that affect economic damages (like cost of future care, ability to work, etc.) if those are substantial, since economic damages are uncapped. Sometimes that involves employing additional experts, such as life-care planners or economists, but even your medical expert’s input might inform those damage areas (for example, a medical expert might testify that the patient will need a certain expensive treatment for life). Another MICRA facet: it limits plaintiff attorney fees on a sliding scale. This doesn’t directly affect the expert, but it means the plaintiff attorney must be mindful of costs. Also, MICRA allows defendants to introduce evidence of the plaintiff’s insurance or other benefit payments (the collateral source rule is partially abrogated), which might mean your expert needs to be prepared if they are testifying about future care costs and the defense brings up that some costs are covered by insurance or similar. MICRA also requires a 90-day notice of intent to sue in med mal cases – this is pre-suit, but it often means you might consult an expert even before filing the lawsuit to verify that the case has merit. Indeed, the standard of care typically must be established by expert testimony for the plaintiff to prevail, so plaintiffs generally obtain an expert review pre-filing (though not mandated by law like in some states with “certificates of merit”). In summary, while MICRA’s cap doesn’t change how you present expert testimony at trial, it certainly affects the economics and strategy surrounding expert usage in California malpractice cases. It urges efficiency and wise use of expert resources given the recovery limits. It also underscores the importance of having a very credible expert – juries who know about the cap (they usually aren’t explicitly told, but attorneys often allude to “legal limits”) might only award the full $250k (now $350k+) if they are truly convinced by the expert that the harm was significant.
  
  

• Standard of Care Definition: In California malpractice law, the standard of care (what the plaintiff must prove the defendant deviated from) is generally defined as that level of skill, knowledge and care in diagnosis and treatment that other reasonably careful practitioners would use in similar circumstances, based on the learning and skill ordinarily possessed by reputable members of the profession in the same field. This is usually established by expert testimony. It’s worth noting California case law expects that if the defendant is a specialist, the standard of care is that of practitioners in that specialty, and if board-certified, sometimes the national standard is considered (since board certification is national). Your expert should articulate the standard of care in a way consistent with California law. The jury instructions (CACI) on standard of care often guide this phrasing. Ensure your expert doesn’t inadvertently hold the defendant to a higher or different standard than California law recognizes. For example, an expert might personally do extra steps out of caution, but they should distinguish personal practice from the minimum standard required. Similarly, causation in California (for injury cases) is the “substantial factor” test – your expert must often say that the negligence was a substantial factor in causing the harm, which essentially means it was a significant contributor (more than trivial). Be sure they use the right terminology (e.g., avoid saying “100% caused” or conversely “maybe caused”; substantial factor or reasonable medical probability of causation is the target language).

By understanding these California-specific standards, you can better prepare your expert and structure their testimony to meet the necessary legal criteria. It’s not enough for an expert to be persuasive; their testimony must also survive admissibility challenges and conform to the legal definitions at play. Fortunately, California’s evidentiary framework, while unique in some aspects, is navigable with careful preparation. In summary: qualify your expert properly (§720), ensure their testimony is relevant and based on reliable material (§801), prepare for expansive cross-exam including publications (§721) and compensation (§722), be mindful of the Sargon reliability gatekeeping, and account for how MICRA and other state laws influence the case. With all these in check, your medical expert witness can be a powerful asset in your California litigation arsenal.