The learned treatise hearsay exception (Rule 803(18)).

Learned treatises are great tools to help understand expert testimony. And a hearsay exception lets you read them to the jury. Fed. R. Evid. 803(18). You need to establish foundation for them, though, so let’s talk about that.

You need an expert to identify the source as reliable authority on cross-examination or to rely on it during direct examination. A couple of pointers. First, ensure the authority fits with that expert’s field; don’t ask a neurosurgeon to vouch for an orthopedic surgery article. Second, your expert must be prepared to lay the foundation for the source. For example, if you’re cross-examining the opposing expert and he refuses to acknowledge the source as reliable authority, your expert must be prepared to do it. If that happens, you may want to avow to the court at sidebar that your expert will do so. The court may allow you to use the authority on cross-examination based on your avowal. [Obviously, your expert better be rock-solid on this topic.]??

Many of these authorities are in periodicals. It isn’t enough for an expert to say that the Lancet or Journal of the American Medical Association are reputable publications. The expert must address the specific article’s reliability. E.g., 30B Charles Alan Wright & Arthur R. Miller, Federal Practice & Procedure: Evidence § 6938. That makes sense. Journals sometimes withdraw articles if they discover the data were unreliable or the author used flawed methodology. [Think of the Lancet article from decades ago about the MMR vaccine and autism.] The same approach applies to specific authors. It isn’t enough to note that Dr. Jane Doe is a recognized authority; your expert must know about *this* article by Dr. Doe.??

Remember that the learned treatise is read to the jury—it doesn’t go into the jury room with the jurors. You need to object if that is about to happen. Also, not every state follows the federal approach. While the federal courts let experts use learned treatises to bolster their direct examination testimony, some states limit using them to attack an opposing expert on cross-examination.??

In addition to Federal Practice & Procedure, another treatise I like on this topic is 7 Michael G. Graham, Handbook of Federal Evidence § 803:18 (9th ed.).