Medical malpractice cases are often won or lost based on the testimony of experts. These cases require attorneys to prove two distinct elements: a breach of the standard of care (SOC) and causation, that the breach caused harm to the patient. While both elements are crucial, courts have strict rules about how experts testify, especially when it comes to causation experts and their reliance on SOC opinions.

At Watson & Carroll, we’ve represented clients in complex medical malpractice cases and understand the nuances of using expert testimony effectively. One challenge that often arises is ensuring causation experts provide admissible and compelling opinions without improperly commenting on the SOC. In this blog post, we’ll share best practices to avoid pitfalls when working with causation experts.

1. Separate Breach from Causation

To succeed in a medical malpractice case, you must clearly distinguish the roles of your experts:

  • Standard of Care (SOC) Breach: This is addressed by an expert in the defendant’s specialty (e.g., a radiologist in a radiology case). This expert establishes how the defendant deviated from what a competent provider in the same specialty and locality would have done.
  • Causation: This testimony addresses how the breach (if proven) caused harm to the patient. Causation experts must frame their opinions as hypothetical, assuming that the breach occurred, rather than opining on whether the breach actually happened.

2. Frame Causation Opinions Hypothetically

Causation experts that have not been disclosed as SOC experts must not give an opinion on whether the SOC was breached. Instead, they should explain what would have happened if the breach had not occurred. This ensures their testimony remains within the bounds of causation. In a case involving blood in the spinal column causing compression on the spinal cord leading to paralysis, the following question and answer is an example of how to provide a causation opinion that survives a defense challenge:

Attorney: “Doctor, I’m not asking you to comment on whether Dr. S breached the standard of care. Assume for the purposes of this question that Dr. S identified and reported the hematoma in the spinal column (blood). If that had occurred, what would have been the likely outcome for Mr. L?”

Expert: “If the hematoma had been identified earlier, surgery could have been performed sooner, significantly reducing or even preventing the patient’s paralysis.”

This approach avoids improper commentary on the SOC breach while focusing the expert’s testimony on the link between earlier diagnosis of blood in the spinal column and the patient’s subsequent injuries.

3. Use the SOC Expert as the Foundation

The SOC expert’s testimony must lay the foundation by clearly establishing the breach. Only after this is done should the causation expert testify to explain how the breach impacted the patient. This sequence avoids redundancy and maintains clarity for the jury.

Courtroom Flow:

Standard of Care Expert Testifies First:

Example: “Dr. S deviated from the standard of care by failing to identify and report the hematoma (blood) that was visible in the spinal column on the CT scan.”

Causation Expert Testifies Second:

Example: “If the hematoma had been reported, the surgery would have occurred sooner, preventing the complications.”

4. Prepare Experts to Stay in Their Lane

Ensure your causation expert understands their role and avoids commenting on the SOC. Here’s how:

  • Clearly Define Their Role: The causation expert should state that they assume the breach occurred, based on the SOC expert’s testimony.
  • Focus on the Causal Link: Their testimony should address how the breach (if proven) led to harm.
  • Avoid Overstepping: They should avoid phrases like “I think the defendant should have done X.” Instead, they can say, “Assuming X was done, the injury could have been avoided.”

5. Avoid Asking the Causation Expert if They Agree with the SOC Expert

While it may seem logical to ask the causation expert if they agree with the SOC expert, doing so can create unnecessary risks:

Blurring Roles: The causation expert’s role is to assume the breach, not validate or critique the SOC expert’s conclusions.

Opening the Door: Such questions invite the defense to exploit inconsistencies or argue that the causation expert is improperly opining on the SOC.

Instead, frame the causation expert’s reliance on the SOC expert’s conclusions as a hypothetical:

Better Question: “Have you reviewed Dr. Jones’s opinions regarding the standard of care?”

Better Answer: “Yes, I reviewed and assumed Dr. Jones’s conclusions for my analysis of causation.”

Experts can rely on hearsay when forming their opinions under Rule 703 of the Federal Rules of Evidence and its state equivalents, including Nebraska’s Neb. Rev. Stat. § 27-703, IRE 5.703 in Iowa, and SDCL § 19-19-703, South Dakota. This rule allows experts to base their opinions on facts or data that are not admissible in evidence if those facts or data are of the type reasonably relied upon by experts in the particular field.

For example, a orthopedic causation expert may rely on a radiologist SOC expert’s deposition testimony about a missed hematoma on a CT scan because medical professionals routinely incorporate radiological findings into their analysis of outcomes.

6. File Pretrial Motions to Clarify Testimony Scope

If you anticipate challenges to your experts’ testimony, consider filing a motion in limine to establish their permissible boundaries:

Breach: Addressed solely by the SOC expert.

Causation: The causation expert assumes the breach for purposes of their opinion.

Sample Argument: “The causation expert’s testimony does not address whether the standard of care was breached. Instead, it assumes the breach occurred as a hypothetical and focuses solely on the injury’s preventability.”

7. Build Redundancy in Expert Testimony

Relying on a single expert for SOC or causation is risky. Retain multiple qualified experts to:

  • Establish the SOC (e.g., two radiologists).
  • Support causation (e.g., orthopedist spine surgeon, emergency department physician).
  • This redundancy ensures the case remains strong even if one expert’s testimony is excluded.

8. Align Causation Experts with SOC Experts

Causation experts should review the SOC expert’s credentials and opinions to ensure consistency and alignment. This does not mean validating or critiquing the SOC expert but being familiar enough to base their causation analysis on those findings.

Key Steps:

  • Review the SOC expert’s conclusions about the breach.
  • Ensure the causation expert’s timeline and assumptions align with the SOC expert’s testimony.
  • Frame reliance as hypothetical: “Assuming Dr. Jones’s opinion that the standard of care was breached is correct, I have analyzed the consequences of that breach.”

Conclusion

Using causation experts effectively requires careful planning, clear boundaries, and coordination with SOC experts. By following these best practices, you can strengthen your case and avoid common pitfalls in medical malpractice litigation. At Watson & Carroll, we’re committed to providing clients with the highest level of representation, ensuring every expert plays their role effectively.

Need help navigating expert testimony in your malpractice case? Please contact us today to get your case started at (402) 991-2100. We can discuss what steps you will need to do to protect your rights and build a winning case.