Physician's expert testimony must stay within the 'reasonable confines' of their practice area

Physician’s expert testimony must stay within the ‘reasonable confines’ of their practice area; Court limits the testimony of Internal Medicine Expert Witness regarding the spread of COVID-19

In the case brought by Plaintiff Leonard Roberts against Defendants Philadelphia Express Trust, Hapag-Lloyd USA, LLC, and Marine Transport Management, Leonard Roberts had alleged that he contracted COVID-19 while working as a longshoreman on a vessel with an individual who had tested positive for COVID-19. His Amended Complaint included claims for fraudulent concealment under Georgia law and negligence under Section 905(b) of the Longshore and Harbor Workers’ Compensation Act (“LHWCA”)

The Court partially granted Defendants’ motion, dismissing Plaintiff’s fraud allegations and the alternative claim for negligence. The Court also determined that the duty to intervene was not violated, nor was it triggered simply because the Defendant failed to remove the infected person from the vessel or isolate them. However, the Court did not dismiss Plaintiff’s Section 905(b) claim for breach of the turnover duty, which comprises the “duty of safe condition” and the “duty to warn.” Claims related to these duties are typically subject to an “open and obvious” defense, which means that hazards should be observable and physical, affecting a specific work area or component of a ship. The Court was unable to determine as a matter of law that the individual allegedly infected with COVID-19 on the vessel constituted an “open and obvious” hazard. Typically, open and obvious hazards are physical and observable risks that affect a specific work area or component of a ship, like an unprotected walkway. 

During the discovery phase, Defendants identified Dr. Mitchell Adam Blass as a retained expert witness who would provide expert testimony at trial. Blass, an internal medicine and infectious disease doctor, expressed his expert opinion in a written report. He opined that, within a reasonable degree of medical probability, Plaintiff did not contract COVID-19 from his actions working on board the vessel PHILADELPHIA EXPRESS on July 11-12, 2020. Blass also suggested that Plaintiff could have contracted COVID-19 from various other sources, including contact with his girlfriend, who had COVID and worked as a waitress at the time. 

In response, Plaintiff moved to exclude Blass’ opinions. The basis for this motion was twofold: first, it was argued that Blass’ report did not meet the requirements of Federal Rule of Civil Procedure 26(a)(2), and alternatively, it was contended that his opinions should be excluded under Federal Rule of Evidence 702, Daubert v. Merrell Dow Pharmaceuticals, Inc, and its progeny. 

Internal Medicine Expert Witness 

Mitchell Adam Blass, M.D., completed his Bachelor of Science in Biology from Emory University and then graduated with his medical degree from Emory University School of Medicine. He is board certified in both internal medicine and infectious disease. He completed an internal medicine residency at Emory University Affiliated Hospitals. He was employed as a Hospital Epidemiologist at Saint Joseph Hospital of Emory university for six years.

Discussions by the Court 

Before turning to the substance of Blass’ opinions, Plaintiff had initially challenged the completeness of Defendants’ expert disclosures under Rule 26. Plaintiff had argued that Blass’ report did not adequately explain the bases and reasons for his opinions and failed to disclose the facts and data he considered when forming them. Specifically, Plaintiff objected to the report for not including a reference to “data of COVID-19’s incubation time” and for lacking a reference to information from the Center for Disease Control (“CDC”) website, which Blass testified he relied on to formulate his opinions. Plaintiff contended that these deficiencies had hindered their ability to prepare for an effective cross-examination of Blass during his deposition, and therefore, some sanction under Rule 37 was warranted. 

However, the Court had conceded that despite the shortcomings in Blass’ report regarding the identification of the basis and reasons for his opinions, as well as the facts and data considered, sanctions under Rule 37 were not warranted. 

Even though Blass’ report was found to be deficient under Rule 26, Defendants had successfully demonstrated that the deficiency was harmless. They had pointed out that one of the factors the Court considered in determining whether a Rule 26 violation was substantially justified or harmless was “the surprise to the party against whom the evidence would be offered.” Defendants had argued that Plaintiff could not have been surprised by their expert’s reliance on CDC guidance, as they had referenced the same guidance in their communications with Plaintiff before Blass’ deposition. Additionally, the transcript of Blass’ deposition showed that Plaintiff’s counsel had conducted a thorough cross-examination. Therefore, Defendants had shown that, despite the report’s deficiencies, Plaintiff was not surprised by Blass’ reliance on CDC guidance and COVID-19 incubation time, and even if there had been surprise, no harm had resulted from it. 

Furthermore, Plaintiff’s counsel had the ability to address any limited surprise by requesting more specific disclosures, seeking a discovery extension, or attempting to resolve the dispute in other ways, but they had not taken these steps. This lack of action weighed against any exclusionary measures under Rule 37. 

Because Defendants had successfully demonstrated that any deficiency in Blass’ report was harmless under Rule 37, the Court had denied Plaintiff’s request to exclude his testimony based on a Rule 26 violation. 

Plaintiff had challenged Blass’ testimony on three grounds. First, Plaintiff had argued that Blass was not qualified to testify about the spread of COVID-19. Blass had opined that, within a reasonable degree of medical probability, Plaintiff did not contract COVID from his actions working on the vessel and that Plaintiff could have contracted COVID from various other sources. Plaintiff had contended that Blass lacked the qualifications to provide these opinions because Blass had testified that contact tracing was “outside of the scope” of his practice. 

Blass, however, was a licensed physician with over 20 years of experience and was board certified in both internal medicine and infectious disease. He had worked as a Hospital Epidemiologist at Saint Joseph Hospital of Emory University for six years and had started studying COVID in the first quarter of 2020. Blass had extensive experience, having cared for a substantial number of COVID patients on a daily basis for over two years. The Court had explained that having a medical degree alone does not automatically qualify a physician to testify about any medical issue; the physician’s expert testimony must stay within the reasonable confines of their practice area. In this case, the Court found that Blass’ opinions were within the reasonable confines of his experience as an epidemiologist and infectious disease physician, making him qualified to offer them. Any concerns about the difficulties of contact tracing were considered matters that affected the weight of his testimony rather than its admissibility. 

Plaintiff had further challenged Blass’ methodology. Plaintiff objected to Blass relying on his experience in patient care to form his conclusions and criticized his opinions for being based on a limited subset of material that wouldn’t reliably support his expert opinions regarding where Plaintiff contracted COVID-19. Plaintiff pointed out that Blass lacked detailed knowledge of the ship’s layout and hadn’t taken any measurements. Additionally, Blass hadn’t reviewed the medical records of the crew member who had COVID or Plaintiff’s girlfriend, which left gaps in his understanding of the situation. Plaintiff also highlighted that Blass didn’t have information about his living arrangements with his girlfriend. 

In response, Defendants argued that Blass had reviewed deposition transcripts that provided him with sufficient facts to support his opinions. They contended that Blass’ extensive experience as an infectious disease physician, when applied to the facts of the case, was sufficiently reliable for his opinion that Plaintiff did not contract COVID from his actions on the vessel. 

However, Defendants had not met their burden in laying a sufficient foundation for Blass’ second opinion, which suggested that Plaintiff could have contracted COVID from various other sources. The Court excluded this second opinion as unreliable. 

As for Blass’ remaining opinion, Plaintiff argued that Blass’ testimony about the ways in which a person can, or, more importantly, cannot contract COVID-19 wouldn’t be helpful to the jury but the Court begged to differ considering Blass’ testimony delved into areas beyond the understanding of the average layperson. The Court determined that this opinion was relevant to Defendants’ defense against Plaintiff’s remaining claim and was not subject to exclusion under the helpfulness requirement. 


Plaintiff’s motion to exclude the testimony of Dr. Mitchell Adam Blass was granted in part and denied in part by the Court. The Court has not arrived on an outcome for this case since the remaining issues involved in this case still await resolution. 

Key takeaways:

  • This case demonstrates the importance of ensuring expert disclosures and reports comply fully with Rule 26. Deficiencies can still provide grounds to attack expert opinions unless proved to be justifiably harmless. Parties have the ability to cure any limited surprise by requesting more specific disclosures, seeking a discovery extension, or otherwise attempting to resolve this dispute 
  • The decision also illustrates how courts serve a gatekeeping role under Daubert in assessing the admissibility of expert opinions. Qualifications alone do not suffice. Parties must also establish the reliability of the expert’s principles and methods. When expertise is the primary basis, as with Blass, experts must explain precisely how their experience supports their conclusions. Opinions unsupported by sufficient methodology may be excluded. 
  • Additionally, the Court excluded one opinion as unreliable even while allowing another admissible opinion by the same expert. This shows the Daubert requirements apply on an opinion-by-opinion basis. Admissibility of one opinion does not guarantee admissibility of all opinions by the same expert. 
  • Lastly, the Court rejected a challenge that the expert testimony would not assist the jury. As the Court discussed, testimony need only address matters beyond ordinary lay knowledge to have relevance and be helpful.  
  • In summary, this case serves as a guide for properly admitting expert opinions under the Federal Rules of Evidence and Daubert standards. Compliance with Rule 26, establishing reliable methodology, and basic relevance are key to admissibility.