Lawyers can cross examine experts by questioning them with a “learned treatise” – what a non-lawyer might describe as an authoritative book or article written by an expert in the field. For example, if a doctor is testifying at trial in a medical malpractice case, her opinion on the proper standard of medical care can be challenged, on cross examination, by showing her a “learned treatise” that conflicts with her testimony. The jury hears the quote from the book, and can take it into consideration in evaluating the weight it may give to the expert’s testimony.
This is what happened in Kace v. Liang, a wrongful death medical malpractice case. In this case the doctor-defendant was testifying. He was shown pages from the web sites of Johns Hopkins University School of Medicine and Mayo Clinic that impeached his testimony, and at the request of the attorney questioning him, he read them to the jury.
On appeal the defendant argued that the web pages did not satisfy the strict requirements associated with learned treatises under Massachusetts law, and the Massachusetts Supreme Judicial Court agreed, stating that
The content of the web pages indicates that they are not medical ‘treatises’ of any sort intended to be read and used by physicians, but rather are directed at laypersons. . . . To establish the admissibility of the statements taken from the Johns Hopkins and Mayo Clinic Web sites, the plaintiff’s counsel was obligated to show that the author or authors of the web pages was or were “a reliable authority.” . . . The credibility of Johns Hopkins and Mayo Clinic as highly respected medical institutions or facilities is not enough to demonstrate the reliability of statements on individual pages of each institution’s Web site. There is nothing to say who wrote each Web page, or whether the author of each Web page was an appropriate source of information … .
This is not to say that material on a website may never be used as a learned treatise on cross examination. As the Court noted, it is up to the party seeking to use the material to establish that it was authored by a “reliable authority,” something the plaintiff had been unable to do in this case.
Despite this holding, the Court upheld a 2.9 million dollar jury verdict in favor of the plaintiff, holding that this, and several other errors, did not result in undue prejudice to the defendant.