By Dr. Ken Broda Bahm:
The expert has prepared thoroughly for her testimony before the judge. She knows each opinion and every foundation. The outline that counsel developed is all but memorized. But then, as she is about an hour into describing the detailed methods and conclusions, the judge’s eyes are drifting down to the table and the nods of understanding have stopped: He isn’t getting it. In itself, there is nothing in the testimony that is impossible to understand – on the contrary, it is organized and clear. But the judge seems to have disengaged. Instead of tracking with the testimony at each step, he is just hearing detail after detail and letting it wash over him. And if there were a jury in the room, the problem would be even worse.
What went wrong? The problem is that the expert and her attorney haven’t given the judge a clear reason for listening. They are prioritizing clarity but leaving the relevance generally implicit. The judge knows what the testimony is, but not why it is important. More specifically, the judge isn’t being told what matters most in choosing between this expert and the one on the other side. Having listened to quite a few plans for expert testimony, I believe that there are two general ways to go about it: a descriptive way (here is what I did, and why, and what I concluded) and a comparative way (here is why, at every level, my conclusions are stronger than those offered by the adversary). In my view, the comparative approach is stronger because it puts relevance first, it tells judges or juries exactly why they are hearing each of these details. The comparative approach will still cover all of the basic descriptive details, but within a different frame. The comparative frame is one that motivates the listener, keeping free-floating description to a minimum, and instead, emphasizing up-front and at every stage why they should believe you over the alternative.
Why Comparison Works
Listening, when it truly is listening, is an active process, not a passive one. At our best, we don’t simply hear, understand, and remember. We know what to do with the information, what purpose it serves, and what mental bucket it goes into. Comparison facilitates this kind of motivated listening by clarifying the relevance. By either responding to or preempting an opposing expert, the comparison allows the judge or jury to avoid abstract detail and, instead, stay focused on the choice of who to believe and why. Of course, this is not up to the witness alone. The attorney asks the questions, and often that means sticking with the conventional but somewhat boring approach of just walking through background, method, and conclusions point-by-point in descriptive fashion.
In the next section, I will contrast the same testimony delivered in descriptive and comparative fashion.
An Example
I will be using the scenario of a defense expert in a products liability case. Following a batted-ball injury in a little league baseball game, the Plaintiff claims that the Defendant’s bat was manufactured to put too much speed on the ball. Whether the bat at issue passed or failed the test meant to measure and to limit this exit speed is the crux of the dispute between the two experts.
As you read through each of the examples below, ask yourself which is more clear, more engaging, and which paves the way for a judge’s or juror’s subsequent decision.
Descriptive Testimony
Attorney: Dr. Jones, will you tell us a bit about your professional background?
Expert: Certainly, I was a professor in physics and mechanical engineering for 12 years at the University of Illinois, but a little over 20 years ago, I moved into the sporting goods industry and since then I have been engaged in testing the actual performance of a variety of products, including baseball bats.
Attorney: And you have had the opportunity to evaluate the bat in question in this case?
Expert: Yes, I have. My goal was to look at the bat to determine whether the bat legitmately passed or failed the BESR test.
Attorney: And what is the BESR test?
Expert: It stands for “Ball Exit Speed Ratio,” and it refers to the measured speed of the ball as it comes off the bat after being hit.
Attorney: Okay, and how did you go about measuring that?
Expert: Using the same machine employed by regulators, we fired 100 balls at the bat and measured the speed of each ball as it came off.
Attorney: And what did you do then?
Expert: We calculated a mean ball speed, as well as a standard deviation on all of these ball speeds, and then we treated all balls that were measured at more than three standard deviations away from the mean, in either direction, as statistical outliers.
Attorney: What is a “statistical outlier”?
Expert: In any measurement situation, especially one like this where there are only very, very small distinctions, you are going to have some values that are just odd because they are far outside of the norm. The standard practice is to exclude those values because they are often the result of machine error, measurement error, or some unknown anomaly.
Attorney: Okay, thank you Doctor.
Comparative Testimony
Attorney: Dr. Jones, did you have the opportunity to review the report from Dr. Smith, the Plaintiff’s expert?
Expert: Yes I did, and I was also here in court when Dr. Smith was testifying.
Attorney: Do you believe that there is a difference in the work experience of you and Dr. Smith?
Expert: Yes I do. Dr. Smith is an accomplished academic in mechanical physics. He has a good reputation, and he deserves it. But he has never been engaged in the practical mechanics of product testing. In contrast, I have worked in that field for the past 20 years. And I can tell you, there is a difference between what works in theory and what works in practice.
Attorney: Dr. Jones, in this case, Judge Davis knows that the Plaintiff is claiming the bat fails the BESR test and the Defense is claiming that the bat passes it. How do you reconcile this conflict?
Expert: That conflicting result boils down to just one fact: Dr. Smith included statistical outliers and I, consistent with industry and regulatory practice, did not include statistical outliers.
Attorney: Okay, why don’t you take a moment and explain this idea of statistical outliers.
Expert: Certainly. In any task where you’re measuring very small variations, you need some way to separate the signal from the noise – to know what is meaningful data and what is garbage. So the standard practice – the one I followed along with the industry and the regulators – is to define as an “outlier” any ball speed measure that is more than three standard deviations away from the mean.
Attorney: More than three standard deviations above or below the mean?
Expert: Right, in either direction, if it is that extreme a measurement, it is suspect and we exclude it. In this case, we excluded more slow measurements than fast measurements.
Attorney: But you did exclude some fast measurements?
Expert: Yes, based on that criteria and based on industry and regulatory practice. Measurements that are that far from the average are likely to be machine error, measurement error, or some unknown anomaly. It doesn’t make sense to include them.
Attorney: Did Dr. Smith include them?
Expert: Yes he did, and that played a decisive role in raising the ceiling for Dr. Smith’s measured speed.
Attorney: In your view, is that a good practice.
Expert: Absolutely not. It is garbage data. If you believe each of Dr. Smith’s measurements, including the outliers, the results would defy physics.
Attorney: What is the better practice in your view?
Expert: Not just the better practice, but the only acceptable practice is to have some way of cleaning the data. Otherwise, you are measuring error.
Attorney: Thank you doctor.
While one could imagine a legal audience getting the point via either mode of presentation, it should be clear that the comparative version is more engaging and effective in focusing on the listeners’ conclusions and helping them decide which side is more likely to be right. Some attorneys and witnesses worry that too much focus on the other side can sound defensive. But when the comparison is framed as a reason to choose you over them, it is offense not defense.
It is also worth noting that the comparison may be, as in this case, expert versus expert, but that is not the only comparison. Jurors or judges may also be choosing between the expert and nothing, or between the expert and the version of “common sense” that they brought with them into the courthouse. In either case, the principle is the same: Facilitate motivated listening by focusing not just on information, but on choice.
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Other Posts on Expert Witnesses:
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Photo Credit: 123rf.com, Used under license