It needs no citation of authority to say that an expert is the most difficult witness to cross-examine.  United States v. 23.76 Acres of Land, 32 F.R.D. 593, 596 (D. Md. 1963)

Her job is not an easy one, because she is engaging in high stakes battle with an articulate, knowledgeable, and experienced adversary. Easton, AMMUNITION FOR THE SHOOT-OUT WITH THE HIRED GUN’S HIRED GUN: A PROPOSAL FOR FULL EXPERT WITNESS DISCLOSURE, 32 Ariz. St. L.J. 465, 504 (Summer, 2000).

Cross-examination of an expert is very difficult, and often provides little useful information. Graham, APPLICATION OF THE RULES OF EVIDENCE IN ADMINISTRATIVE AGENCY FORMAL ADVERSARIAL ADJUDICATIONS: A NEW APPROACH, 1991 U. Ill. L. Rev. Online 353, 377 (1991)

How difficult is cross-examining an expert?  To many, it is an unenviable and daunting task.  The expert knows the subject matter inside and out (or is supposed to) and by that status alone has a decided advantage over the questioner.  But cross-examine we must – except of course, when there is nothing in dispute and no proper means to disparage credibility, so a structured approach and ‘game plan’ are necessary.

This article will be begin by surveying what various advocacy experts suggest, and in part 2 it will propose a comprehensive outline for designing a response to the opposing party’s expert.

In FUNDAMENTAL TRIAL ADVOCACY, 2nd EDITION, Professor Charles Rose offers “Seven Basic Principles of Cross-Examining Experts.”

  • Preparation is the key.
  • Limit the scope of direct testimony through voir dire & objections.
  • Know the subject area of expertise.
  • Gather all relevant evidence to support cross.
  • Connect case analysis to the expertise of the witness.
  • Identify the basis of the expert’s testimony.
  • Decide strategically whether to voir dire the witness when opposing counsel attempts to tender the witness as an expert.

In a follow-up “checklist, Rose includes exploring bias and motive and the important reminder to “[s]tay on the Island” unless prepared.

Perrin, Caldwell & Chase’s THE ART AND SCIENCE OF TRIAL ADVOCACY, lists “potential areas of inquiry” including

  • Constructive facts and areas of agreement
  • Attacking qualifications
  • Attacking motivation
  • Attacking the expert’s basis
  • Attacking opinions

Steven Lubet’s MODERN TRIAL ADVOCACY (Law School Third Edition) offers an “Expert Testimony Opposition Checklist.”

  • Can you challenge the witness’ credentials?
  • Can you obtain favorable information from the witness?
  • Can you challenge the witness’ impartiality?
  • Can you point out omissions by the witness?
  • Can you substitute information to make the witness’ opinion more favorable to your case?
  • Can you challenge the witness’ technique or theory?

Lubet is also a proponent of seeking to extract beneficial information early, before an attack.

The classic CROSS-EXAMINATION: SCIENCE AND TECHNIQUES (2nd EDITION) by Pozner and Dodd offers surprisingly little on the specifics of expert witnesses.  The text offers the observation that “the best method of cross-examination of the opposing expert is not to discuss the things the expert has done, but the [important] things he has not done.”

Are these approaches sufficient?  The suggestion here is that there is more, a combination of applying evidentiary rules and cross-examination theory and technique to properly challenge an opponent’s expert.  These steps will be articulated in part 2 of this article.