Plaintiffs often disclose medical experts to opine not only as to the diagnosis or prognosis of an injury or medical condition, but also as to whether the defendant’s actions caused plaintiff’s alleged injury/condition. In the usual course of treatment, physicians often focus simply on the diagnosis a patient’s injury/condition, rather than on what caused it. Thus, when medical records contain statements regarding causation, those statements typically derive solely from a patient’s own subjective statements. It is therefore important to distinguish between a patient’s subjective causation statements and objective medical evidence.

Generally, experts are precluded from commenting on the credibility of a plaintiff patient. However, an expert does not comment on a plaintiff’s credibility by disagreeing with them.

Further, courts are not required to admit opinion evidence based on a plaintiff’s subjective statements. However, because causation is a fact question for the jury, the best way to explore ipse dixit opinions is through careful cross examination.

Below is a six-step methodology taken from the American Medical Association’s Guides to the Evaluation of Disease and Injury Causation, 2^nd Ed. (“Causation”), which may be helpful when cross examining a medical expert whose causation testimony is based on a patient’s subjective statements, as opposed to objective medical evidence.

• Step 1 – Identify Evidence of Injury/Condition: Establish the specific opinions the medical expert holds regarding the patient’s injury and diagnosis. Distinguish between diagnosis and causal analysis. Obtain all the data upon which the expert bases his or her diagnosis. In doing so, get the expert to distinguish between objective medical evidence (e.g., physical exam, radiology records, lab results, etc.) versus the patient’s subjective statements.
• Step 2 – Review and Assess Available Epidemiologic Evidence: Prior to the cross examination, collect all the available epidemiologic literature regarding the patient’s injury/condition. In cross examining the expert, identify the design for each study and assess the methods for each study. Ask the expert about the statistical significance of certain studies and the degree in which chance may have produced certain results. Based off the expert’s testimony regarding these studies, explore whether the expert can draw a conclusion as to the causal connection between the incident and the injury/condition based on the epidemiologic literature.
• Step 3 – Obtain and Assess Evidence of Exposure: Ask the expert whether he or she knows how the injury occurred. If the expert answers affirmatively, ask specific questions regarding the cause, such as the patient’s administration of the drug at issue, the patient’s exact movement on the date of the incident, the muscles the patient may have used during the incident, or the amount of force generated by alleged trauma. In response to these questions, the expert will likely admit that his or her knowledge derives solely from the patient’s own statements. It is also helpful to question the expert on whether he or she performed any tests on the patient to determine whether his or her subjective statements align with objective evidence.
• Step 4 – Consider All Relevant Factors: Examine the expert regarding his or her knowledge of other risk factors that could potentially cause the injury. Specifically, ask the expert whether he or she is aware of any prior injuries or psychological factors that could cause or contribute to the patient’s symptoms. When inquiring about other relevant factors, ask how strongly other factors are associated with the patient’s injury and how strongly epidemiologic studies may address them as confounders.
• Step 5 – Judge the Validity of Testimony: After the expert has admitted that other events or injuries could have caused the injury, determine how much weight the expert places on a patient’s subjective statements. Often times, the expert may admit that he or she does not always believe a patient and will admit that a patient’s self-reporting is subjective, not objective, evidence. Further, some jurisdictions permit evidence of secondary gain, where a patient has secondary, outside motivations such as litigation for reporting to his or her physician. Compare Yingling v. Hartwig, 925 S.W.2d 952, 955 (Mo. Ct. App. 1996) with Lawrence v. MountainStar Healthcare, 320 P.3d 1037, 1054 (Utah App. 2014). A medical expert is likely familiar with secondary gain and may admit that it is an important factor in considering the cause of an injury. Get the expert to admit any inconsistencies between the patient’s subjective statements and the objective medical evidence, e.g., patient reports 10/10 pain but exhibits no objective symptoms of pain (increased heart rate, sweating, antalgic gate, etc.). In Missouri, also consider:
  • Mo. Rev. Stat. § 490.065 provides “(3) The facts or data in a particular case upon which an expert bases an opinion or inference may be those perceived by or made known to him at or before the hearing and must be of a type reasonably relied upon by experts in the field in forming opinions or inferences upon the subject and must be otherwise reasonably reliable…”. 
  • Mo. Rev. Stat. § 491.010 “1. No person shall be disqualified as a witness in any civil suit or proceeding at law or in equity, by reason of his interest in the event of the same as a party or otherwise, but such interest may be shown for the purpose of affecting his credibility.”
• Step 6 – Generate Conclusion: Finally, after exploring the validity of subjective testimony, get the expert to admit that, outside of what the patient subjectively reported, he or she has no way of knowing the cause of the injury. Inquire as to what, if any, specific knowledge, skill, experience, training, or education the expert may have in forensic causal analysis as it relates to the specific circumstances of the alleged incident and the patient’s injury/condition. Get the expert to admit that his or her opinion as to causation under the specific circumstances of the case is not based on his or her knowledge, skill, experience, training, or education, but merely on the subjective statements of the patient.

Examples of Legal Authority Reviewed

Peterson v. Nat’l Carriers, Inc.,972 S.W.2d 349 (Mo. Ct. App. 1998)

Duerbusch v. Karas, 267 S.W.3d 700 (Mo. Ct. App. 2008)

Myers v. Illinois Cent. R. Co., 629 F.3d 639 (7th Cir. 2010)

Hendrix ex rel. G.P. v. Evenflo Co., Inc., 609 F.3d 1183 (11th Cir. 2010)

Gopalratnam v. Hewlett-Packard Co., 877 F.3d 771 (7th Cir. 2017)

Yingling v. Hartwig, 925 S.W.2d 952 (Mo. Ct. App. 1996)

Lawrence v. MountainStar Healthcare, 320 P.3d 1037 (Utah App. 2014)

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