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Impeachment of Experts by Medical or Scientific Literature – Alan W. Clark

Written August 3, 2021

This article will explore the subject matter of impeachment of expert witnesses by the use of medical or scientific literature containing contrary opinions during cross-examination. The expert must first concede that the author or work is “Authoritative on the subject matter at issue. This foundation is often magical, elusive and frustrating to elicit from the opposing expert who typically will not want to concede that any treatise or work is authoritative thereby denying an effective means of cross- examination. This article reviews the various circumstances and use of “Authoritative literature during cross examination of experts. As such literature is generally considered inadmissible hearsay evidence for the truth of the matter stated, violations of this rule by opposing counsel have led to reversal of jury verdicts. See Mark v. Colgate 53 A.D. 2nd 884 (1st Dep’t 1976); Labate v. Plotkin, 195 A.D.2nd 444 (2nd Dep’t 1993; Watkins v. Labiak, 6 A.D.3rd 426 (2nd Dep’t 2004). Various definitions and suggested language to establish an adequate foundation will be discussed. The Federal Rules of Evidence providing a more liberal use of learned treatises will also be discussed.


In the seminal case of Egan v. Dry Dock, East Broadwav and Battery Railroad Company.,12 A.D.556 (1896 ) the First Department permits the cross-examination of the defense e x p e r t by use of statements in two books on the subject of design, construction and operation of boilers which books the expert knew and admits were standard works on engineering subjects.

The Court explains:

“…There is no doubt that the contents of scientific books cannot be read to a jury for the purpose of proving the facts or establishing the deductions stated in them. The reasons for this rule are so thoroughly stated in the text books that it is not here necessary to comment upon it. But the contents of the books which are referred to in this particular case did not come within that rule. Whenever a man holds himself out as an expert witness and undertakes to give his opinion upon any scientific matter, it is not only proper to examine him as to the grounds of his opinion, but his qualifications as an expert may be tested upon cross-examination in any way which will enable the jury, who are to pass upon the weight to be given to his testimony, to judge intelligently about it. For that purpose it is perfectly proper to ask him whether or not the opinion he has expressed agrees with the opinion of other people who are conceded to be learned upon the same subject, because, if an expert witness admitted that the opinion which he expressed was contrary to the opinion which was held upon the same subject by other men who were acquainted with the same science, it might, unless the reasons which he gave for his opinion were satisfactory, tend strongly to detract from the weight which that opinion would otherwise receive.”

In Hastings v. Chrysler Corp.,273 A.D. 292 ( 1948 ) the First Department discussed the rule as follows:

The opinions expressed in treatises or recognized authority which are at variance with those given on the stand by the expert may not be received in evidence. (**527 McEvoy v. Lommel, 78 App.Div. 324,327, 80 N.Y,S. 71,73): the reference to them has no bearing on their truth or validity; they are used only as tending to impeach the witness on the stand with respect to his knowledge or the subject on which he professes to be an expert. If the expert does not concede the authoritativeness of the literature attempted to be resorted to, it may not be used on cross-examination.” Further, this Court states:

“Cross-examination for discrediting purposes along the lines mentioned is not, as respondents contend, limited to text-books or literature to which the witness (without objection) has referred on his direct examination. Of course, any misstatement of a witness may be developed on cross-examination. Nor is the practice confined to those cases only where the witness •295 testifies that he has read the book concerning which he is being questioned. Where an expert testifies that he has read the treatise, the scope of the examination may be broader; but that does not affect the general application of the rule that treatises, which the witness concedes are authoritative in character, may be used to impeach the testimony given by him.”

In lthier v Solomon, 59 A.D. 2nd 935 (2nd Dep’t 1977), the Second Department in agreeing with the First Department as to the rule states:

“It is well settled that an expert may be questioned through the use of a scientific work or treatise. However, in order to lay a foundation for the use of such material, he must first admit to its authoritativeness (People v. Feldman, 299 N.Y. 153, 85 N.E.2d 913; Mark v. Colgate Univ., 53 A.D.2d 884, 385 N.Y.S.2d 621; Hastings v. Chrysler Com., 273 App.Div. 292, 77 N.V.S.2d 524; Richardson, Evidence (Prince 10111 e d.), s 373). In the case at bar, appellant was never confronted with

a specific work or treatise and asked whether he considered it authoritative. Rather, he was asked which books he considered authoritative. These questions were altogether too broad.”

To the contrary is Bryant v. Bui, 265 A.D.2nd 848 (1999),

The Supreme Court, Appellate Division, Fourth Department held that: (1) physician was properly ordered to provide names of books he found authoritative”

The Court explains:

“With respect to question (a), defendant stated that there were “ two, three or four” books that he found authoritative, and thus the court properly ordered him to provide the names of those books. Any material that may be used as evidence-in-chief or for rebuttal or impeachment is discoverable (see, CPLR 3101)

Allen v. Crowell-Collier Pub/. Co., 21 N.Y.2d 403,407 288 N.Y.S.2d449,235 N.E.2d 430). An expert may be cross-examined on a textbook only after the expert has accepted the textbook as authoritative (Labate v. Plotkin, 195 A.D.2d 444,445,600 N.Y.S.2d 144).”

Improper cross-examination by defense counsel of plaintiff’s expert led to reversal by the Second Department in Labate v. Plotkin, 195 A.D.2nd 444 (1993)) in which the Court states:

..However, during cross-examination the defense counsel improperly utilized hearsay statements from medical textbooks and articles which the plaintiff’s experts had not accepted as authoritative. It is well settled that on cross-examination an expert witness may be confronted with a passage from a treatise or book which contradicts the opinion the expert witness previously expressed on the stand, only after the expert witness has accepted the treatise or book as authoritative (see Mark v. Colgate Univ., 53 A.D.2d884, 886). In light of the numerous instances in which the defense counsel utilized passages of books not accepted as authoritative, we find that the plaintiff was unduly prejudiced and is entitled to a new trial (se e, Mark v. Colgate Univ., supra., 53 AD2d at 886). We note that although the defense counsel did not read directly from the books, his questions clearly indicated to the jury that the statements which he read off his notepad were taken from those texts.”

However, a physician is not allowed to foreclose full cross-examination on a treatise by the semantic trick of denying the work is authoritative after the physician relies on the published article on direct and later says” it [the article] is of value” and “I agree with a lot of what they [the authors] said.” Spiegel v. Levy , 201 A,D. nd 378 ( 1st Dep’t 1994 ). Also see Winiarski v. Harris, 78 A.D.3rd 1556 ( 4th Dep’t 2010 ).

Improper use of medical literature by defense expert during direct examination caused the Second Department in Lipschitz v. Stein, 10 A.D.3rd 634 (2004) to reverse a defense verdict and grant plaintiff a new trial stating :

Although opinion in a publication which an expert deems authoritative maybe used to impeach an expert on cross-examination (see People v. Feldman, 299 NY 153, 168 [1949]; Watkins v. labiak. 6 AD3d 426 [2004]; Labate v. Plotkin, l 95 AD2d 444,445 [1993]; Mark v. Colgate Univ., 53 AD2d 884, 886 [1976]), the introduction of such testimony on direct examination constitutes impermissible hearsay (see Kelly v. St. Luke’s Hosp. Of Kansas City, 826 SW2d 391,

396-397 [Mo App 1992]; Niagara Vest v. Alloy Briquetting Corp., 244 AD2d 892, 893 [1997]). In any event, the expert testified on cross-examination that he did not consider any books or articles in the field of infectious diseases “authoritative.””

Affirmative use of article by the defense expert in Lipschiiz. supra. was improper as he was wrongly permitted to testify over objection as to the results of a published ” Endophthalmitis Vitrectomy Study” regarding the most common sign of endophthalmitis and as to the time of presentation of this infection after cataract surgery.

The Court states:

“The EVS was not admitted into evidence and its reliability was not established. Accordingly, testimony with respect to the EVS should not have been admitted (see Niagara Vest Alloy Briquetting Corp., supra at 893).”

Compare Kearney v. Papish, 136 A.D.3rd 690 (2nd Dep’t 2016), where the plaintiff’s expert relied on the publication in rendering his opinion and then on cross examination denied the work was authoritative. The Second Department upholds

the trial court’s ruling allowing cross-examination from the publication, holding:

Contrary to the plaintiff’s contention, the trial court did not err in permitting the use of a publication from the American College of Emergency Physicians to be used during

cross-examination of the plaintiff’s expert physician. On cross-examination, an expert witness may be confronted with scientific works or publications for impeachment purposes where the material has been deemed authoritative by such expert (see People v. Feldman, [24 N.Y.S.3d 710] 299 N.Y. 153, 168, 85 N.E.2d 913; Lipschitz v. Stein, 10 A.D.3d 634, 635, 781 N.Y.S.2d 773; Labate v. Plotkin, 195 A.D.2d 444, 445, 600 N.Y.S.2d 144; Mark v. Colgate Univ., 53 A.D.2d 884, 886, 385 N.Y.S.2d 621). Here, the plaintiff’s expert testified that he had relied on the subject publication in rendering his opinion in this case. He described it as “excellent, well put together, useful clinical guidelines,” and he found it “[u]useful [,] clinically relevant, [and] well thought out, well researched.” Despite his reliance on the publication and general praise for it, the expert witness refused to acknowledge that the publication was “authoritative” because he had “some issues with the word ‘authoritative’ ” and did not “think that anything that a human being does is authoritative.” A physician may “not foreclose full cross-examination by the semantic trick of announcing that he did not find the work authoritative” where he has already relied upon the text and testified in substance that he finds it reliable and trustworthy (Spiegel v. Levy, 201 A.D.2d 378, 379, 607 N.Y.S.2d 344; see Wolf v. Persaud, 130 A.D.3d 1523, 1525, 14 N.Y.S.3d 601; Lenzini v. Kessler, 48 A.D.3d 220, 851 N.Y.S.2d 163 ; cf. Knutson v. Sand, 282 A.D.2d 42, 46, 725 N.Y.S.2d 350 ).

But defense counsel’s misquoting of passages from an article plaintiff’s expert conceded was authoritative during cross-examination was reversable error leading court to vacated dismissal of the complaint. Watkins v. Labiak, supra. In an interesting lower court opinion, an expert (defendant’s expert) was permitted to testify on direct examination to specific peer review articles and treatises that support her opinion without discussing specific contents of literature which is inadmissible hearsay. Brown v. Speaker, 2008 NY Slip Op 32184 (u), J. Joan B. Carey relying on People v. Sugden, 35 N.Y.2nd 453 (Professional reliability rule). Further, Plaintiff’s expert was properly permitted to be cross-examined on a Journal Article where the expert conceded the medical Journal itself was authoritative and article was subject to scientific and peer review scrutiny.

However, the Court of Appeals in Hinlicky v. Dreyfuss , 6 N.Y.3rd 636 ( 2006 ) holds that clinical practice guidelines containing algorithm published by medical association and used by defendant Anesthesiologist to evaluate patient’s preoperative need for cardiac evaluation were admissible for defense as non-hearsay demonstrative aid. The court notes that plaintiff’s attorney did not timely object to questions regarding the process the defense Anesthesiologist followed in using the “clinical guidelines” in deciding not to obtain a preoperative cardiology work-up. Plaintiff’s attorney never requested a limiting instruction. The Court did not reach the “professional reliability “argument stating:

648 Defendants additionally maintain that the algorithm was properly admitted under the professional] reliability exception to the hearsay rule, which enables an expert witness to provide opinion evidence based on otherwise inadmissible hearsay, provided it is demonstrated to be the type of material commonly relied on in the profession (see e.g., Hambsch v. New York City Tr. Auth., 63 N.Y.2d 723,726,480 N.Y.S.2d195,469 N.E.2d

516 [1984]; see also Prince, Richardson on Evidence§ 7-311 [Farrell 11th ed.]). Because the trial court’s proper basis for admitting the algorithm was demonstrative and plaintiff made no request for clarification or limiting instructions, we need not reach this issue. We note only that whether evidence may become admissible solely because of its use as a basis for expert testimony remains an open question in New York (see People v, Goldstein, 6 N.Y.3d 119, I26-127. 810 N,Y,S.2d 100, 843 N.E.2d 727 [2005] [concerning out-of-court factual statements] ). While some jurisdictions allow otherwise inadmissible materials relied upon by an expert witness to reach the jury for nonhearsay purposes, we have acknowledged the need for limits on admitting••t292 the basis of an expert’s s opinion to avoid providing a “conduit for hearsay” (idat 126,810 N.Y.S.2d 100,843 N.E.2d 727). Absent timely objection by plaintiff, however, we need not decide whether in this instance the trial court applied proper limits in allowing the algorithm to be viewed by the jury to evaluate the experts’ opinions or for some other nonhearsay purpose.”

Compare Lenzini v. Kessler ,48 A.D.3rd 220 (2008), where the First Department in upholding a defense verdict held:

55 [1998]). In the subject medical malpractice trial, the court did not improvidently exercise its discretion in authorizing the use of certain material for impeachment purposes as against plaintiffs’ expert witnesses. Plaintiffs’ expert in radiology was, in that regard, questioned about a medical text he had brought to court, made notes thereon, and clearly deemed sufficiently authoritative notwithstanding that he may not have accepted everything contained in it.

As for plaintiffs’ expert in gynecology, he expressly recognized the reliability of the material about which he was cross-examined.

Indeed, a physician may “not foreclose full cross-examination by the semantic trick of announcing that he did not find the work authoritative” where he has already relied upon the text and testified that “he agreed with much of it”(Spiegel v. Levy, 201 AD2d 378,379 [1994), lvdenied83 NY2d 758 [1994]).”

In Halls v. Kivici, 104 A.D.3rd 502 (2013 ) the First Department upheld the defendant’s testimony and admission of the clinical guidelines of the American Gastroenterological Association regarding the frequency of performing colonoscopies depending on cancer risk. However, the Court reversed the defendant’s verdict holding that the patient was entitled to a limiting jury instruction with regard to this evidence.

The Court states as follows:

“…The court’s instruction as rendered failed to make clear to the jury that the Guidelines were simply recommendations regarding treatment, and thus, that compliance with the Guidelines **425 did not, in and of itself, constitute good and accepted medical practice (see Spensieri v. Lasky, 94 N.Y.2d 231, 701 N.Y.S.2d 689, 723 N.E.2d 544 (1999]; see also Sawyer v. Dreis & Krump Mfg. Co., 67 N.Y.2d 328,337,502 N.Y.S.2d 696,493 N.E.2d 920 [I 986]).

The trial court should have given the jury an instruction specifically stating that the Guidelines were not the same as standards of care and that the jury was to make its determination based on the particular circumstances of the case, not on the Guidelines alone.

Introducing the Guidelines into evidence without the appropriate limiting instruction allowed the jury to infer that a physician need not exercise professional judgment with regard to individual patients, but could simply abide by the recommendations promulgated in the Guidelines.”

The cross-examiner may consider foundation questions using “google “search of dictionaries definition of Authoritative “as: Able to be trusted as being accurate or true, reliable; Synonyms; dependable, trustworthy, sound, authentic, valid, Recognized or evident authority. authoritative author is someone generally considered an expert in his/her field or specialty.

Compare the more liberal Federal Rules of Evidence: Rule 803(18) provides the following are not excluded by the rule against hearsay, regardless of whether the declarant is available as a witness:

“(18) Statements in Learned Treatises, Periodicals, or Pamphlets. A statement contained in a treatise, periodical, or pamphlet if: the statement is called to the attention of an expert witness on cross-examination or relied on by the expert on direct examination; and the publication is established as a reliable authority by the expert’s admission or testimony, by another expert’s testimony, or by judicial notice. If admitted, the statement may be read into evidence by not received as an exhibit.” (Emphasis added)

In Tari v. McGann , 697 F.2d 75, the Second Circuit in explaining the history of this Rule explains:

” Prior to the enactment of Rule 803(18), learned treaties were generally usable only on cross-examination, and then only for impeachment purposes. Sec Weinstein, supra. i 803(18)[01]. Most commentators found the hearsay objections to learned treatise evidence unconvincing, and recommended that treatises be admitted as substantive evidence. Some commentators went so far as to suggest that treatises be admitted independently of an expert’s testimony. Id. ‘!1803(18)[02]. The Advisory Committee rejected this position, noting that a treatise might be “misunderstood and misapplied without expert assistance and supervision.” Fed.R. Evid. 803(18) advisory committee notes. Accordingly, the Rule permits the admission of learned treatises as substantive evidence, but only when “an expert is on the stand and available to explain and assist in the application of the treatise…” Id.”


Unfortunately, what’s frustrating to Trial attorneys is that the word “Authoritative” is not always clearly defined thereby continuing to give it a magical,” God

Like quality and elusive meaning which has been misinterpreted by experts and attorneys to obfuscate and block a means of effective cross-examination. Counsel should take the time to establish a proper evidentiary foundation to show the literature or author is authoritative. Perhaps it’s time the Courts adopt a broader more pragmatic definition of “Authoritative based on case precedent as originally set forth in Egan,supra., over 124 years ago which is simply whether the expert acknowledges the a u t h o r or literature as a recognized, standard , accepted , reliable and/or trustworthy authority or expert in the field. This is more of an objective than subjective way of establishing “Authoritative “and prevents an expert from disingenuously blocking effective cross­ examination of contrary opinions or facts by simply denying that the literature is authoritative.


*ALAN W. CLARK is a Trial attorney and Of Counsel to The Law firm of Duffy & Duffy, PLLC, 1370 R & R Plaza, Uniondale, NY 11556 and Managing Partner of The Law Firm of Alan W. Clark & Associates, LLC., Huntington Station, New York. Mr. Clark is Board Certified and Recertified in Medical Professional Liability by the ABPLA and for the past 43 years represents injured patients. Mr. Clark is a sustaining member of AAJ; NYSTLA; NCBA; NYSBA; and Board of Trustee Emeritus NYLS. SCBA and ABPLA. He also serves on the Board of Directors NYSTLA and lectures for numerous Bar Associations.

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