The Limits of Medical Expert Testimony

Parties are often tempted to consolidate expert witness testimony where possible due to the cost of both obtaining and producing it at trial.  For instance, why pay four medical experts to testify at trial if you can get by with only one?  Before choosing that strategy, do the qualifications and opinions of the experts actually overlap?

I will use a real-life example to illustrate the problem.  David Oliveri, M.D. is a local physiatrist whom seemingly everyone in the community, including me, has hired at some point.  He is polite, personable, responsive, and generally makes a good witness.  Deposing him is a pleasant, professional experience for me, and I hope him too.  The only problem for Dr. Oliveri is not necessarily his fault.  Some lawyers, personal injury plaintiffs primarily but I have seen defense do it too, hire him as the sole medical expert in a case, rather than incurring the cost of paying multiple treating physicians.  This is perfectly acceptable, except when attorneys rely upon Dr. Oliveri to testify beyond the scope of his expertise.  This puts Dr. Oliveri, or any expert for that matter, in an untenable position.



An expert witness may testify only within the limited scope of his knowledge.

First, remember Nevada’s requirements for expert testimony.[1]  NRS 50.275 permits expert testimony “[i]f scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by special knowledge, skill, experience, training or education may testify to matters within the scope of such knowledge.”  To testify, an expert “must be qualified in an area of ‘scientific, technical or other specialized knowledge’ (the qualification requirement).” [2]  Hallmark outlined factors to consider in determining whether a proposed expert is appropriately qualified to offer an opinion.  “(1) formal schooling and academic degrees, (2) licensure, (3) employment experience, and (4) practical experience and specialized training.  We note that these factors are not exhaustive, may be accorded varying weights, and may not be equally applicable in every case.”[3]

Dr. Oliveri’s qualifications include a board certification in electrodiagnostic medicine and physical medicine and rehabilitation, also known as physiatry.[4]  A physiatrist is a physician who specializes in physical medicine and rehabilitation or administers physical therapy.[5]  His residency training was in physical medicine and rehabilitation.  He describes his scope of practice as “[o]ffice consultation and treating physician for patients with musculoskeletal, neuromuscular, and spine injuries or disorders.” The scope of his private practice, however, is primarily providing rehabilitation services through HealthSouth Rehabilitation Hospital in Las Vegas.  He has never practiced as a surgeon.  Based upon these qualifications, Dr. Oliveri is likely qualified to testify as an expert witness in physiatry.

Again, the problem only arises when attorneys attempt to consolidate too much and rely upon Dr. Oliveri in fields beyond physiatry.  For instance, a personal injury plaintiff will ask Dr. Oliveri if all of her medical treatment is causally related to whatever happened, but fails to consider if the scope of her medical treatment fits within Dr. Oliveri’s qualifications.  This overreach leads to problems satisfying Hallmark’s scope requirement.   For instance, in one matter where a personal injury plaintiff disclosed Dr. Oliveri as her sole medical expert, his report concluded that pain management injections were causally related, but Dr. Oliveri has no experience in pain management.  Dr. Oliveri also concluded that an orthopedic surgery was causally related to the accidents, but he has no expertise in orthopedic surgery and is not a surgeon.  The same problem arose when plaintiff relied upon Dr. Oliveri to attack the defense orthopedic and neuroradiology opinions.

I have also seen personal injury plaintiffs rely upon Dr. Oliveri for work capacity opinions.  A work capacity opinion is a two step process.  First, a physician establishes the medical activity limits for a patient.  Then a vocational counselor assesses what jobs that patient can do within those restrictions.  As a physician, Dr. Oliveri is likely able to perform step one.  The problem only arises when attorneys ask him to perform step two.  Dr. Oliveri has no training or experience as a vocational counselor or rehabiliationist.  He has no qualifications or training to conclude a plaintiff should work in jobs classified as sedentary or light, will likely have attendance problems, or have a reduced work life.  By skipping the vocational counselor expert, the entire work capacity opinion fails.

The scope also includes overlapping fields.

However, the scope of permissible expert testimony from a given expert witness is not often capable of mathematic precision.  Dr. Oliveri’s qualifications as a physiatrist could permissibly overlap into other fields where he could testify.

Boone v. Commerce Ins. Co. noted “there is some overlap among practitioners who are licensed in different practice areas.”[6]  It concluded “a licensed orthopedic surgeon would be qualified to treat most of the same type of injuries that a chiropractor could treat.”[7]  California follows a somewhat similar analysis, in that it allows “experts in one profession to testify as to the malpractice of practitioners in a related profession or discipline when there is commonality or ‘overlap’ between the two professions and the malpractice claim implicates that commonality or overlap.”[8]  It is vital when arguing overlap, however, to actually provide the court with admissible, reliable evidence showing an overlap.  Mere argument that an overlap exists is not a sufficient evidentiary basis.

How far does overlap go?  It has been addressed extensively in Mississippi.  In Bailey Lumber & Supply Co. v. Robinson[9] the Supreme Court of Mississippi addressed a trip and fall case where Robinson alleged he required a total hip replacement surgery due to his fall.  After falling, Robinson initially sought medical treatment from an internal medicine and pulmonary medicine specialist, Dr. McNair.[10]  Dr. McNair observed certain limitations to Robinson’s left hip, suggested surgery might be needed, and referred Robinson to an orthopedic surgeon.  At trial, Dr. McNair testified although Robinson had a pre-existing condition in his left hip before the fall, “the fall had aggravated his condition to such a degree that hip-replacement surgery was necessary. Dr. McNair testified that, in his thirty-year career, he had treated hundreds of patients with hip problems related to fractures, osteoarthritis, and hip-replacement surgery, but acknowledged that he was not a specialist in orthopedic surgery.”[11]

Robinson’s two orthopedic surgeons also testified.  The first concluded any exacerbation from the fall “would have lasted approximately two weeks to one month, and he attributed Robinson’s need for a hip replacement to pre-existing arthritis.”[12]  The second concluded “the fall would have aggravated Robinson’s pre-existing condition, but that any complications as a result of the fall would have subsided within three or four months” and had not caused the need for hip replacement surgery.[13]

The trial court had allowed Dr. McNair to testify that “Robinson had osteoarthritis in his hip before his fall at Bailey Lumber, but the fall had injured the already-damaged hip and the condition had been aggravated to such a degree that hip-replacement surgery was necessary.”[14]  The Supreme Court of Mississippi concluded it was error to allow this testimony.

First, the court reviewed Dr. McNair’s qualifications and conceded he was a proper “medical expert in internal medicine and primary care.  Under that designation, Dr. McNair certainly was qualified to opine regarding diagnosing a hip problem, referring a patient to an orthopedic surgeon, or making other evaluations from the standpoint of a primary-care or internal-medicine physician.”[15]  However, it was error to allow Dr. McNair to testify outside that area.  “With regard to Dr. McNair’s testimony as to the cause of Robinson’s need for a hip replacement, we find that Dr. McNair, an internal-medicine physician with a subspeciality in pulmonology, does not satisfy the qualification and reliability standards” for expert testimony.[16]

Mississippi law, like Nevada, did recognize that “a physician does not have to practice in, or be a specialist in, every area in which he offers an opinion, but he must demonstrate that he is sufficiently familiar with the standards in that area by his knowledge, skill, experience, training, or education” to qualify as an expert witness.[17]  But Mississippi law does not allow a medical expert to testify about any topic merely because the expert has medical training.  While “a specialist in a particular branch within a profession will not be required, we have gone on to say, only if the witness possesses scientific, technical, or specialized knowledge on a particular topic will he qualify as an expert on that topic.”[18]

Bailey Lumber then highlighted prior Mississippi cases applying that standard.  Troupe v. McAuley affirmed excluding opinion testimony from a neurosurgeon who was offered to testify about the standard of care for a neuro-otolaryngologist.[19]  Neurosurgery concerned surgery upon the head, scalp, skull, brain, and arteries leading to the brain, but neuro-otolaryngology requires additional training in ear, nose, and throat surgery.[20]  Troupe concluded the neurosurgeon lacked sufficient familiarity with the standards of neuro-otolaryngology and could not give expert testimony in that specialty.[21]

Cheeks v. Bio-Medical Applications, Inc.[22] affirmed excluding opinion testimony from a family physician who was offered to testify about the standard of care for a dialysis clinic.  To testify, the physician “must have been familiar with the standard of care to which a dialysis clinic, a nephrologist[,] and a radiologist are held.”[23]  However, the family physician “had no special training or experience in the field of nephrology,” “had never participated in a dialysis procedure,” and instead “relied on the expertise of a nephrologist” for his patients’ dialysis treatments.[24]

Applied to Dr. McNair, Bailey Lumber found he was obviously well qualified to testify “as an expert in internal medicine and as a primary-care physician.”[25]  However, again, Dr. McNair’s testimony should have ended there.  He testified a referral to an orthopedic surgeon had been necessary “because Dr. McNair was not qualified to perform the hip surgery or even to render a final opinion regarding Robinson’s need for the surgery.”[26]

Dr. McNair testified that in his thirty-year career, he had treated hundreds of patients with hip-related problems related to fractures, osteoarthritis, and hip-replacement surgery, but conceded that he was not a specialist in orthopedic surgery. Orthopedic surgery is surgery on the bones, joints, and musculoskeletal system. Dr. McNair does not have specialized training in orthopedics, he did not do a residency or a fellowship in orthopedic surgery, he is not board-certified in orthopedic surgery, and he has not done any research or published any articles related to orthopedic surgery or hip replacements. Dr. McNair is not a surgeon of any type, and he candidly admitted that when he has a patient who he believes needs a hip replacement, he refers the patient to an orthopedic surgeon. Dr. McNair testified that he would not determine when or how to perform a hip replacement; the orthopedic surgeon would make those decisions.[27]

Ultimately, the proper scope of Dr. McNair’s testimony should have been limited to “diagnosing a hip problem, referring a patient to an orthopedic surgeon, or other evaluations made from the standpoint of a primary-care or internal-medicine physician.”[28]  However, he “was not qualified to offer expert testimony regarding whether the fall at Bailey Lumber was the cause of Robinson’s need for a hip replacement.”[29]

Bailey Lumber & Supply Co. continued its analysis and found that even had Dr. McNair been qualified, his testimony was unreliable.  No evidence had been offered “that Dr. McNair consulted any literature, applied a particular theory, performed any procedures, or relied on any principles, methodologies, or scientific methods in concluding that the need for the hip replacement was a result of Robinson’s fall at Bailey Lumber.”[30]  “He did not apply any known and tested theories, consult any literature, or rely on any principles, methodologies, or scientific methods in reaching his conclusion, nor did he have personal experience as an orthopedic surgeon.  McNair did not provide a basis for his conclusion….”[31]



Do not gloss over the details.

I understand the economic pressure to retain only the expert witnesses who are absolutely necessary.  However, those pressures must be reconciled with the limits of an expert’s qualifications.  As one court memorably put it, the “world’s most respected cardiologist might not be qualified to testify about the operation of nuclear reactors, and the world’s top nuclear physicist might not be qualified to value an injured person’s lost future income.”[32]  Put another way, merely obtaining a M.D. does not qualify a person to testify on any healthcare related topic just as merely obtaining a J.D. does not qualify a person to testify on any legal topic.


[1] If you do not practice here, just know that Nevada has an awkward relationship with Daubert in that Daubert has simultaneously been adopted and rejected.

[2] Hallmark v. Eldridge, 124 Nev. 492, 498, 189 P.3d 646, 650 (2008).

[3] Id. at 499, 189 P.3d at 650-51.

[4] All of this information is from his CV and depositions I have taken of him.

[5] Stedman’s Medical Dictionary.

[6] 884 N.E.2d 483, 488 (Mass. 2008).

[7] Id.

[8] Enslen v. Kennedy, 127 Cal.App.4th 1448, 1458 (2005).

[9] 98 So. 3d 986 (Miss. 2012).

[10] Id. at 989.

[11] Id. at 990.

[12] Id.

[13] Id.

[14] Id. at 991.

[15] Id. at 992.

[16] Id.

[17] Id. (internal quotations omitted).

[18] Id. (quoting Worthy v. McNair, 37 So. 3d 609, 616 (Miss. 2010) (emphasis in original)).

[19] 955 So. 2d 848, 858 (Miss. 2007).

[20] Id. at 849 n.2, 852.

[21] Id. at 856, 858.

[22] 908 So. 2d 117 (Miss. 2005).

[23] Id. at 120.

[24] Id.

[25] 98 So. 3d at 993.

[26] Id. at 994.

[27] Id.

[28] Id.

[29] Id. (emphasis in original).

[30] Id. at 995.

[31] Id. at 996.

[32] Norwest Bank, N.A. v. Kmart Corp., 3:94-CV-78, 1997 U.S. Dist. LEXIS 3426, 3, 1997 WL 33479072 (N.D. Ind. 1997); Schuck v. Signature Flight Support of Nev., Inc., 126 Nev. Adv. Op. 42, 245 P.3d 542, 546 n.7 (2010) (“SCR 123 prohibits citation to unpublished orders and opinions issued by the Nevada Supreme Court. This ban does not extend to federal district court dispositions, which may be cited for their persuasive, if nonbinding, precedential value.”).