The art of taking expert witnesses down

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Don’t waste your ammunition trying to blow away an expert witness’s testimony. Most good experts will simply fire their opinions back in your face.

That’s the advice of Thomas M. Durkin, a veteran trial lawyer and partner at Mayer, Brown, Rowe & Maw in Chicago. Instead, he suggests, limit your attack during cross-examination to particular areas where you have the possibility of discrediting the expert.

“An expert is by definition a lot smarter than you,” said Durkin. “They know their stuff better than anyone else in the courtroom, and certainly better than the lawyers.

“Often with an expert you can hurt yourself because experts are often very glib and very certain of their opinions, and it’s very difficult to shake them from their opinions,” he said. “You just reinforce what they have to say.”

Besides, he added, if your own expert is going to rebut the other side’s expert, there’s no point spending a lot of time duplicating those efforts.

Durkin honed his cross-examination skills during more than 50 jury trials over 13 years as an assistant U.S. attorney. In private practice, he has polished these skills defending white-collar criminals and handling a variety of civil cases throughout the country.

The most effective way to cross-examine an expert witness, Durkin said, is to “go after small points.”

It’s better than just declining the right to cross-examine an expert witness, which will only give the expert more credibility in the jury’s eyes.

“If you just say ‘no’ to cross, they’re going to assume it’s a weakness on your part,” he said.

If you choose your targets carefully, you may actually take down the expert a few notches.

Pointing out bias

During a lengthy patent infringement case in Buffalo, N.Y. several years ago, Durkin ignored large portions of the opposing expert’s substantive testimony. Instead, he focused on all the areas in which the opponent’s expert was not giving an opinion.

Here is an excerpt from that cross-examination:

Q: Sir, you haven’t heard the evidence in this case, is that correct?

A: No.

Q: And you haven’t made any credibility determinations yourself of any witness that sat in the same chair you’re sitting in now, correct?

A: That is correct.

Q: You’re not offering an opinion in this case on whether or not there’s infringement of the patents either, correct?

A: That is correct.

Q: And you’re not offering an opinion on whether or not the patents are valid, is that correct?

A: Yes.

Durkin said he generally steers clear of asking how much the opponent’s expert is being paid, since his expert is also being paid. But if the expert is a so-called professional witness who spends most of his time testifying or preparing to testify at trials, it’s possible to show the jurors his bias by focusing on his expert-witness income. For example:

Q: Now, you’re a law school professor, is that correct?

A: Yes.

Q: You spend a lot of time, though, working as an expert witness, is that correct?

A: I spend roughly one-third of my time on what I would call working in preparation for possible expert testimony.

Q: And that involves either testifying in court, or testifying in depositions, or preparing to testify in one or the other, whether it works out that you testify or not, correct?

A: That’s correct.

Q: Now, you obviously charge a standard rate as an expert witness, correct?

A: Yes.

Q: And how much is that?

A: Four hundred dollars an hour.

Q: And how much money do you make on a yearly basis as an expert witness?

A: I’d say over the past five years, it’s probably run a little bit in excess of three hundred thousand dollars a year.

On occasion, Durkin has even managed to generate some humor while cross-examining expert witnesses. During that long patent trial in Buffalo, for example, the plaintiff’s attorney had set up a display of his expert’s eight-volume treatise on patent law. Although the jury had been impressed with the expert on direct examination, Durkin was chipping away at his credibility during his cross-examination because of what appeared to be a conflict of interest in his testimony.

“I simply asked him to go to the index and find the section that dealt with ethics and conflicts of interests. I knew it wasn’t there,” Durkin recalled.

The questioning triggered a few smirks and snickers among the jurors, and when Durkin mentioned the testimony again in his closing argument, he actually got a laugh from one of the jurors.

“And in a three-month trial, if there’s something they remember and you get a laugh, you’re successful,” Durkin said.