Category Archives: Expert Witnesses

November 24, 2017

Experts, Tell a Visual Story

By Dr. Ken Broda-Bahm:

When you think of science, do you think of dry research articles, charts and graphs that take a good deal of explanation in order to get to a point? Or do you think of Neil DeGrasse Tyson explaining the Cosmos with the help of clear but sophisticated video and graphics? If it is your goal to connect with an audience of non-scientists, like a jury for example, then your choice ought to be for something closer to the latter. A science-educator like Tyson, who uses all the tools available, is in a better position to make the material not just informative, but engaging and emotional as well.

In a past post, I shared the example of a four-minute video from Tyson on the science of public understanding of science, specifically. That video nicely illustrates the thesis of a group of researchers from Griffith University in Queensland, Australia (Czaran, Wolski & Richardson, 2017). Their paper, like this post, probably should have been a video, because it makes the case that researchers should stretch themselves to step outside the typical forms and outlets of the academy and should tell the story of their research, and use modern media to do so. That advice to distill the research outcome to “short, relatable, digestible, and engaging visual products” applies to expert witnesses as well. This post shares a few of their conclusions, based on their 12-month review of a new service designed to encourage researchers to use audio-visual media to tell their research story as they apply to the testifying expert.

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June 1, 2017

Experts, Talk Like a Normal Human

By Dr. Ken Broda-Bahm: 

Reg human expert img

The expert takes the stand, his credentials proudly displayed to the jury as he launches into the dissertation of his testimony. Amid the complex chains of reasoning, the opaque references to other testimony, and the indecipherable jargon, it seems that he is giving an opinion on the case. But the impression the jury gets is “learned” and “detailed” but, unfortunately, not “helpful.” And when it comes time to deliberate, they’re likely to fall back on their own intuitions and experiences instead of using that expert’s opinion. That is what happens when the expert succeeds at his own goal of providing a sound opinion, but fails at the more important goal of good and clear communication. 

A recent article appears in Scientific American: “Why Can’t Scientists Talk Like Regular Humans?” Author Katherine Wu, a Harvard graduate student and director of ‘Science in the News,’ an organization devoted to better communication of science, describes her own experience in being trained to communicate mostly with other scientists in her field, and to dissociate that from the broader public. “The minute I started thinking of the general public as ‘other,'” she writes, “I compromised my ability to be an effective communicator.” The act of becoming an expert separates you from everyone else. She continues, “Suddenly, I was wheeling and dealing in the private, elite trade of science, far from prying eyes. I felt as though I had been inducted into a secret society: I had transitioned out of the common masses and joined the ranks of the fabled Jedi.” She blames current gaps in the public’s understanding of key scientific concepts, like climate change and genetically modified foods, in part on scientists’ separation from the general public. For expert witnesses, that separation is ultimately destructive to the witness’s goal of communicating in a helpful manner. Wu includes her own list of implications for scientists in the public square, and in this post, I include my own list for those in the witness box. 

Remember that Science and Effective Communication of Science Are Two Different Things 

The expert has two hats: the ‘expert’ and ‘the communicator.’ And when she is on the stand in particular, it is that second hat that needs to be the taller and more spectacular hat. For experts who spend most of their time (properly) on methods and conclusions, it can still be a mistake to treat the communication role as just a simple matter of looking at the jury and dialing down the jargon a bit. Effective teaching of science and other expert subject matters is its own skill, and skill on the subject matter does not mean skill as a communicator. Both need to be worked on. 

This is a particularly important thing to remember since scientists are selected, trained, and rewarded based on their ability to talk to other scientists. Visit an academic conference sometime if you want to be reminded of just how distinct and insular that communication can be. And the higher the expert gets in her field, the smaller the group of ‘peers’ she has and the more specialized (and inaccessible) those conversations become. For an expert witness, you need the right mix of both. And the expert needs to remember that understanding is not the inevitable result. Wu quotes George Bernard Shaw, “The single biggest problem in communication is the illusion that it has taken place.” 

Get Off the Pedestal 

An implied hierarchy says to the expert, “You are better than those sitting in the jury box,” and the court process reinforces that hierarchy. After all, at least until the end of the case, the expert is the only one who gets to offer opinions. But according to Wu, some humility is in order for scientists. “For each and every one of us,” she says, “there is at least one field that is unknown, a field in which someone else considers us the general public.” That includes the jury. They might look like an undifferentiated collection of humans, but the more you know about them as individuals, the more you learn about their sometimes surprising interests and areas of expertise. As an expert, it is not that you’re superior. It is that you are just useful in this one particular context.  

Focus on Method, not Knowledge

Whether a jury, a judge, or an arbitrator, the fact finder who is the audience for your testimony does not want to be in the passive role of just hearing your opinion and accepting or rejecting it. Instead, they want to be in the active role of at least feeling like they arrived at their own conclusion. So looking at it from a fact finder’s eye view, it is not just what you know, it is how you got there. For that reason, the message cannot be just the credentials-based view that reads, “Trust me, I’m an expert.” Instead, the message needs a strong component of “Show your work,” so that, in effect, you are saying, “Let’s work our way to this conclusion together.” Method isn’t infallible, but the right method is better than the alternatives, and more importantly, it provides fact finders with the assurance that they are exercising their own independent judgment and and not just being led along by a fancy expert. 

But Don’t Use Good Communication as an Excuse for Inaccuracy

Adapting should not mean distorting. “When I earn my Ph.D.,” Wu explains, “I might be able to say, ‘We think we may have come across something that explains a minuscule portion of a complex pathway that might be correlated with a slightly elevated risk of contracting this disease—but our findings are pretty specific to this one population studied at this point in time under these conditions.’ Meanwhile, media headlines say, ‘Lemons cure cancer!'” Of course, there is a point at which caveats that sound normal in a scientific context will be misread by the average audience. For example, listeners might reduce Wu’s first statement on her research to ‘We don’t really know much of anything’. Be honest and don’t over claim, but focus on what you do know.  


Other Posts on Expert Testimony: 


Image Credit:, edited, used under license

May 11, 2017

Experts, Take a Lesson from Sally Yates

By Dr. Ken Broda-Bahm: 


Government law enforcement officials have a pretty high profile right now. That’s especially true as they’re increasingly moving into the category of being former law enforcement officials after being removed by President Trump. There was U.S. Attorney Preet Bharara in New York, and more recently, of course FBI Director James Comey who became former FBI Director this past Tuesday. And the day before that, the one in the spotlight was former Acting U.S. Attorney General Sally Yates. She served in that role for only 10 days before being removed by President Trump after refusing to enforce the President’s controversial travel ban. On Monday she testified before the U.S. Senate Judiciary subcommittee hearing on Russian interference in the 2016 presidential election. And, from many sources at least, her testimony has earned high praise. The events have played out like an episode of The West Wing: Already seen as a hero after taking a principled stand on the President’s attempt to partially fulfill a campaign promise to bar Muslims from entering the country, she held her own against the attempts of many GOP Senators to paint her as a partisan, and came off as polite, prepared, and fundamentally tough.

In other words, she came across exactly the way you would want an expert witness to come across. Experts need to be focused on their own role, methods, and conclusions, while also being savvy enough to recognize an attack when they hear one and confident enough to turn some of these attacks back against the other side. I have written before on the advantage of treating cross-examination as a “polite struggle” and in employing the “counterpunch” wherever you can. In my view, Yates’ performance during subcommittee testimony provides a good and timely example of some of the ways that experts can do that. In this post, I will share and discuss some of those examples from her testimony transcript 

Know Your Role

While it was not the topic of the hearing, Sally Yates understood that her earlier decision on the travel ban would come up, because it goes to her credibility. On cue, Senator Cornyn asked about Ms. Yates whether that decision was inconsistent with her role to reasonably defend the actions of the administration. She answered,

It is correct that often times, but not always, the civil division of the Department of Justice will defend an action of the president or an action of congress if there is a reasonable argument to be made. But in this instance, all arguments have to be based on truth because we’re the Department of Justice. We’re not just a law firm, we’re the Department of Justice.

Later on, responding to the same question from Senator Kennedy, she expanded on this point, explaining that any defense of the action would have to include the argument that the executive order had nothing to do with religion, and based on candidate Trump’s past statements, that would be a difficult argument to ground in truth. 

Her response on that theme reflected careful attention to the exact nature of her role, which isn’t to simply defend the administration no matter what, but to reasonably ground her arguments in truth as well. That role parallels the expert’s role, and the approach in answering reflects the expert’s need to display a kind of qualified independence. To Yates, the DOJ is “not just a law firm,” and the legal expert is “not just an advocate.” Always a risk of being seen as a hired gun, a good expert will emphasize a simple and clear explanation of what their role actually is: To conduct an analysis and report those results to counsel no matter what those results turn out to be.  

Know Your Questioner

Consistent with knowing their role, experts like to stay within their box: their area of expertise, their methods, their conclusions. That, of course, is wise. But at the same time, it helps the expert to know their adversary as well. What are their goals and themes? What questions and tactics have they pursued with prior witnesses? Fundamentally, how are they hoping to undermine your testimony? 

In the case of Sally Yates’ testimony, she knew some of the senators would focus on the perceived disloyalty in failing to enforce the President’s order. On that theme, it helped to know what those senators had said previously. Again in response to Senator Cornyn, she clarified:  

Let me make one thing clear. It is not purely as a policy matter. In fact, I’ll remember my confirmation hearing [For Deputy Attorney General]. In an exchange that I had with you and others of your colleagues where you specifically asked me in that hearing that if the President asked me to do something that was unlawful or unconstitutional and one of your colleagues said would just reflect poorly on the Department of Justice, would I say no? And I looked at this, I made a determination that I believed that it was unlawful. I also thought that it was inconsistent with principles of the Department of Justice and I said no. And that’s what I promised you I would do and that’s what I did.

In this case, it was a turn the senators were not able to answer: I only did, she said, what you asked me to commit to doing. 

Answer the Question and the Implication

It is helpful to think of a question as having two parts: the question itself and the implication that the questioner hopes to convey to the audience. When cross-examination is well prepared, the questions aren’t really questions, they’re arguments. The question combined with your response — and sometimes just the question itself, not matter how you respond — carries the intended message for jurors. 

In Sally Yates’ testimony, Senator Cruz tried to convey the argument that the attorney general lacks the authority to defy an order based on simple disagreement. 

Cruz: And if an attorney general disagrees with a policy decision of the president — a policy decision that is lawful — does the attorney general have the authority to direct the Department of Justice to defy the president’s order? 

Yates: I don’t know whether the attorney general has the authority to do that or not. But I don’t think it would be a good idea. And that’s not what I did in this case.

Note that Cruz is asking hypothetically about “an attorney general,” but Yates goes beyond just answering in order to address the obvious implication: “And that’s not what I did in this case.”  

Anticipate and Answer

The coup de grace of Ms. Yates’ testimony was also at Ted Cruz’s expense. In what was clearly intended to be the Senator’s gotcha moment, he brought up the legislative authority for President Trump’s travel ban. Yates, however, anticipated that and came with her own legislative authority that post-dated the Senator’s. Then, she went one better and reframed it as a constitutional issue and not just a matter of legislative wording. The exchange went like this:   

Cruz: By the express text of the statute [8 USC Section 1182], it says, quote, “whenever the president finds that entry of any alien or of any class of aliens into the United States would be detrimental to the interest of the United States, he may by proclamation, and for such period as he shall deem necessary, suspend the entry of all aliens or any class of aliens as immigrants or non-immigrants, or impose on the entry of aliens any restrictions he may deem appropriate.” Would you agree that is broad statutory authorization?

Yates: I would, and I am familiar with that. And I’m also familiar with an additional provision of the INA that says no person shall receive preference or be discriminated against an issuance of a visa because of race, nationality or place of birth, that I believe was promulgated after the statute that you just quoted. And that’s been part of the discussion with the courts, with respect to the INA, is whether this more specific statute trumps the first one that you just described. But my concern was not an INA concern here. It, rather, was a constitutional concern, whether or not this — the executive order here — violated the Constitution, specifically with the establishment clause and equal protection and due process.

Of course, politically, readers might support Cruz or might support Yates. But tactically, the advantage goes to Yates, in my opinion, because she anticipated the argument and prepared for it, then she kept her answer clear, brief, and assertive rather than defensive. Just like an expert should. 


Other Posts on Expert Testimony:


Photo Credit: Renegade98, Flickr Creative Commons 

April 24, 2017

Account for a Lost Faith in Science

By Dr. Ken Broda-Bahm:

Know believe img

This past weekend saw not just Earth Day, but also a nationwide “March for Science.” On Saturday, people across the country, and in some other parts of the world, turned out in order to show support for the role of science. The message behind these marches is distilled in a four-minute viral video from Neil deGrasse Tyson, viewed more than 25 million times in the past few days. Tyson argues that science should help us understand the world and shape public policy, but due to a decline in public support for science, “people have lost the ability to judge what is true and what is not, what is reliable, what is not reliable.” As long as science is viewed as just a chosen and often politicized belief rather than as a means of finding truth, the public won’t have the best guidance on a number of issues like vaccines and medicines, food safety, and climate change. Marchers had the goal of defending scientific knowledge at a time when it is often relegated to just a belief. Critics of the march, however, point out that the idea of large crowds of people marching for science the same way they might march for a political candidate, particularly when most of those marchers seem to represent the left side of the political spectrum, could further erode faith in science, making it seem more like a political stance and less like a neutral source of knowledge. 

The conflict is played out on a background of changing attitudes. As Gallup has been documenting, there has been a decades-long, relatively steep decline in trust in institutions in general. When it comes to attitudes toward science, however, the decline has been even steeper (Gauchat, 2012). Breaking that out by political leaning, however, it appears that most of that decline is the result of changes in one group: Conservatives have gone from being the most science-supporting group to the least supporting group, falling 25 percent in the last four decades. While distrust of science can influence the left as well (research on vaccines or genetically-modified foods for example) (Griffin, 2016), the biggest effect has been that the use of science in supporting regulations or in pointing toward limits to economic development and energy use has meant that conservatives have discounted science in order to maintain cognitive consistency in support of pro-growth policies. Court cases don’t often address the big science behind issues like climate change, but parties do often ask jurors to understand, assess, and apply the scientific method when dealing with the testimony of expert witnesses. For that reason, the waning trust in science itself matters to trial persuasion. In this post, I’ll take a look at a few ways that experts and attorneys can adapt to these changing views of science.  

Voir Dire on Scientific Attitudes

As the data indicate, a creeping distrust of science is not a uniform attitude. It varies, based largely on political viewpoint. So you could use politics as a kind of proxy for views on science. But when your case depends on a jury that holds more favorable attitudes on science, it is even better to ask directly about their views on science: 

Do you tend to see science as just another potentially biased viewpoint, or as a more neutral source of truth? 

Do you think that public funding of scientific research is generally good for society or not? 

Not counting high school, have you had any education or training in science or scientific methods? 

In addition to general questions like these, you can also ask about some of the scientific issues that might relate more specifically to your case, and the reasons your expert is better than theirs: experimental methods, controls, replication, agreement with scientific consensus, etcetera. 

Acknowledge the Problem

Sensitizing people toward a potential bias isn’t a cure, but there’s reason to believe that it can be an antidote of sorts, helping to mitigate the expression or the influence of the bias. If, for example, your expert is going to be relying on government research that could be greeted with skepticism, then it might help to bring the issue up yourself: 

I know that science isn’t always uniformly trusted these days. Perhaps because it has sometimes been misused or even politicized, science can be greeted with skepticism sometimes. But as you listen to the science in this case, no matter which side it comes from, I’d encourage you to focus not just on the conclusions or even on the sources for those conclusions. Instead, focus on the methods. Just like your math teacher did in grade school, you should demand the witnesses to “show your work.” If they followed the right steps, then they should arrive at the most reliable results. So treat it as a method and not just as a belief or an opinion. And you should always be critical of science, but never dismissive of it.  

Try to Escape the Position/Choice Frame

In a way, the problems science faces in the courtroom can be seen as a microcosm of the problems science faces in society. Because research comes from one side’s expert or the other side’s expert, it is easy to see it as just a position that is being adapted to the purposes of the advocate. The act of conducting research itself can also be seen as just marshaling support for a choice you have already made. That “hired gun” effect is something that I’ve written about in an earlier post, and research (e.g., Cooper & Neuhaus, 2000) shows that distrust of experts is common in courtroom settings, but is most pronounced when the testimony itself is complex and hard to understand. When the expert is able to clearly and usefully explain the methods, and to really become a teacher for the jurors, then they’re much less likely to be distrusted as a hired gun. 

In a broader framework, perhaps that same approach applies to the defense of science in general. If scientists take it as their role to do a better job of explaining their approach and teaching the scientific method, if they’re a little bit more like Neil deGrasse Tyson, then perhaps science itself is less likely to be seen as just a hired gun in support of an agenda. 


Other Posts on Attitudes Toward Science: 


Image credit:, used under license, edited. 

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December 22, 2016

Experts, Tell a Story

By Dr. Ken Broda-Bahm: 


By now, it is familiar advice to trial lawyers: Tell a story. Jurors and judges will appreciate the familiar structure, pay greater attention, see the world from your party’s perspective, and have an easier time remembering and using the information. We might think that the advice applies to attorneys, especially during opening statements — and it does. But it doesn’t end there. Rather than being just a handy technique for organizing the attorney’s first presentation, the narrative is a paradigm for how people learn new information and use it. So the advice to “Tell a story” applies in settings wherever people are being taught new information. An expert witness’s trial testimony is one such setting. 

Scientific experts, whether talking about chemistry, design, medical care, or economics, can be hard to follow. Not only is there the unfamiliarity of the scientific language, but jurors and other fact finders often lack a basic understanding of the method and the process as well. Present that in the wrong style — a style that assumes motivation and attention, for example — and it is easy for your audience to shut off. One thing that helps is to frame the unfamiliar science in the familiar structure of the story. A recent study of published scientific literature (Hillier, Kelly & Klinger, 2016) looks at 700 scientific papers on climate change, asking what factors in a crowded literature made some papers more influential than others. What they find is that those papers written in narrative style are more likely to be used and cited in other publications. First author, Annie Hilliar, wrote in a ScienceDaily release,”The results are especially surprising given that we often think of scientific influence as being driven by science itself, rather than the form in which it is presented.” But when it comes to comprehension and influence, form does matter. Science presented in story form made for a more influential contribution.  The expert in trial is not interested in being cited, but does want to be used — by a jury later in deliberations, for example. So rather than following an analytic outline that blandly covers credentials, methods, and conclusions, it is better to turn the testimony into a tale of sorts. In this post, I will break down the steps and provide an example of what this means.  

Story means more than just sequence, and requires more than just following a timeline or interspersing an “and then…” throughout your message. Instead, a story requires the presence of a handful of structural elements that we have come to expect. That story structure helps in providing some recognizable landmarks in your message. 

For each of the components below, I will include an example that was used by an expert I prepared in a past case. The expert, an economist, testified on damages as well as causation on behalf of a products liability plaintiff in a suit over long-term damage caused by an agricultural chemical. 


A scene or situation creates a framework where the action takes place. In scientific testimony, that framework can be the field of scientific inquiry, or it can be a situation giving rise to the challenges addressed by the expert testimony. 

Example: In the agricultural chemical case, the setting is a field — a literal field of crops. That field includes the chemical found to have unexpected long-term effects on crops, but it also includes every other factor that determines yields: water levels, sun and temperature, pests, normal plant diseases.  


The main character in the drama is not necessarily the hero scientist. It could be, but it could also be more abstract: a central idea or concept.  

Example: The white whale for the agricultural economist was the idea of “unique losses:” reductions in yields that are beyond what is normal and expected at a typical farm. 


Every story needs some kind of tension: a challenge to be addressed, a mystery to be solved, or a who-done-it to be answered. 

Example: For each farm and field, the unique losses need to be found. They need to be identified, quantified, and known to be truly unique and beyond the norm. In the process, the expert can’t make assumptions and can’t blame all losses on the culprit chemical, because that falls into the other side’s story and opposing expert’s critique. 


What brings completeness and closure to a story is a solution to the problem, and that solution is also what makes the expert’s story relevant and useful. 

Example: The agricultural economist used historical records and statistical tools, like regression, to control for the other factors: the normal effects of climate, weather, pests and disease. What you are left with after accounting for all of that is the otherwise unexplained effect of the defective chemical. 


Example: Either implicitly or explicitly, a complete story often comes with a moral: a boiled-down message or takeaway that does not depend on full recitation of details, but instead states the point simply. 

Example: For the economist, the message is “the process of elimination.” After accounting for all of the usual suspects for why a particular farm or field would perform less effectively than its average, the loss that is leftover is what can be reasonably attributed to the chemical.

It is not enough for those elements to be just present in the testimony if one takes the time to analyze it in that fashion. Instead, they need to be brought out and linked together in story fashion. Direct examination should start by setting the scene, then move to identifying the central actors and framing the conflict, before finally moving to a resolution and a moral. That isn’t just a matter of art, based on the research, it’s a matter of practical advantage. 


Other Posts on Story: 


Hillier, A., Kelly, R. P., & Klinger, T. (2016). Narrative Style Influences Citation Frequency in Climate Change Science. PLOS ONE11(12), e0167983.

Image credit:, used under license, edited. 

December 1, 2016

Use Credentials Wisely

By Dr. Ken Broda-Bahm: 


This week, the Persuasive Litigator blog reached an important milestone. After being named to the ABA Journal’s “Blawg 100” list for the sixth straight year, we have now ascended to Blawg Valhalla by earning a permanent place in the ABA Journal’s “Blawg Hall of Fame.” Now, I was quick to add the ABA’s badge to Persuasive Litigator’s home page, and won’t be shy in spreading the word. But at the same time, I know what you’re thinking: “If I’m spending my nonbillable time reading this blog, then I don’t care much about your honors, awards, endorsements, credentials and other horn-tooting…I care about whether you can tell me something useful, period.” Well, here is something useful: Jurors are thinking pretty much the same thing when it comes to expert witness credentials. While examination of experts in trial often covers the credentials in great detail, jurors will generally be eager to get to the main event: The conclusions, how the expert got there, and how that can aid a jury in reaching its own decision. The most important thing the jurors are thinking about is how that expert can be useful.  

Naturally, some of the focus on credentialing the expert is required by the law: Rule 702 of the Federal Rules of Evidence requires that an expert be qualified and accepted as an expert by the court prior to offering opinions. So at least some focus on credentials is a legal necessity. But what role do those qualifications play in making the expert influential and persuasive? The answer is, some but not as much as you might think. The research so far seems to indicate that jurors’ use of experts is somewhat complicated. Jurors do base assessments to some extent on qualifications (Shuman, Champagne, & Whitaker, 1996), but the factors that matter most are knowledge, likability, trustworthiness and confidence (Brodsky, Griffin, & Cramer, 2010). But even those qualities don’t guarantee success. In one study (Parrott, Neal, Wilson, & Brodsky, 2015), experts seen as highly knowledgeable were more likable, but not more influential in persuading jurors. For jurors, it isn’t just a matter of finding the expert qualified and then accepting that expert’s conclusions. In this post, I will look at the need to get beyond seeing credentials as just a stamp of approval and share some thoughts on the features of an expert witness that matter the most to jurors. 

One way or another, you will need to cover at least some of your expert’s credentials in order to get that expert admitted. But I think there are three principles to keep in mind when thinking about how and when to cover those credentials when presenting expert testimony. 

One, Knowledge Matters More than Credentials

Rule 702 of the Federal Rules of Evidence does not require credentials per se, but instead requires knowledge. The expert must possess “scientific, technical, or other specialized knowledge [that] will help the trier of fact to understand the evidence or to determine a fact in issue.” That seems to mean, even based on the legal standard, that what you know matters more then how or where you learned it. The implication is to focus your time, not on the stale qualifications (where you went to school, honors, awards, certifications), but on the actual knowledge that sets the expert apart. The expert who is able to communicate their particular skills, tools and experiences relevant to the testimony, will do much better than the experts who just unpack the letters that appear after their names. 

Two, Usefulness Matters More than Either

Research on the so-called “Hired Gun Effect,” (Cooper & Neuhaus, 2000) shows that dislike of highly-paid, frequently-testifying experts tends to occur with both high and low credentialed experts, but is most pronounced when the actual content of the testimony is complex and not easily understandable. In other words, when that information is clear, when the witness is a good teacher and is useful to the listener, then the effect of other factors, including payment, frequency of testimony, and credentials, are mitigated. Taking this blog as an example, I expect that the ABA Journal’s recognition will, at best, get me an extra bit of attention. What matters most is what I do with that attention, and hopefully, it is to convey something useful. That matter of usefulness is the number one issue an expert needs to answer early: “How is it that I can help you reach a just decision?” 

Three, Credentials Are Not the Best Place to Start

The credentials have to precede the opinions, since the court must generally accept that expert as an expert prior to the introduction of opinions. But that does not mean the first thing the jury needs to hear from an expert is a list of credentials. Because the jurors will never be paying greater attention than they are in the first few minutes of an expert’s examination, use those first golden moments for something special right out of the blocks. For example, I think it is a great practice to begin on a point centered on the audience’s need, with a lead-off question like “What are you here to help the jury with?” The answer to that can lead naturally to a consideration of credentials, along with a frame that tells jurors why those credentials are necessary to hear: “What experience or training makes you a good and useful source for that opinion?” It is a functional qualification, not a badge. 


Other Posts on the “Blawg 100:” 


Brodsky, S. L., Griffin, M. P., & Cramer, R. J. (2010). The Witness Credibility Scale: An outcome measure for expert witness research. Behavioral sciences & the law28(6), 892-907.
Cooper, J., & Neuhaus, I. M. (2000). The” Hired Gun” effect: Assessing the effect of pay, frequency of testifying, and credentials on the perception of expert testimony. Law and Human Behavior24(2), 149.
Parrott, C. T., Neal, T. M., Wilson, J. K., & Brodsky, S. L. (2015). Differences in expert witness knowledge: do mock jurors notice and does it matter?. Journal of the American Academy of Psychiatry and the Law Online43(1), 69-81.
Shuman, D. W., Champagne, A., & Whitaker, E. (1996). Assessing the believability of expert witnesses: Science in the jury box. Jurimetrics37, 23.

Image credit: Courtesy of the ABA Journal (Thanks)

November 17, 2016

Hire an Expert Who Doesn’t Want or Need to be Led

By Dr. Ken Broda-Bahm: 

Expert Lead Pic

I recently finished sitting in on a three-week trial, and throughout the testimony, many of the experts were led through their direct. One expert in particular, the other side’s expert thankfully, made it through her entire direct examination without saying anything other than her name, “Yes,” and “That’s correct.” Even on the simple questions, the examining attorney would say, “And you graduated from LSU? Majored in economics? Worked for seven years as a private consultant? Testified for both plaintiffs and defendants, right?” And of course, when it came to her main conclusions, each was presented in a way that enjoyed the attorney’s wording, emphasis, and explanation, not the expert’s. This witness should have played a pretty important role in the trial, answering the question to the extent in which the injured plaintiffs would be able to work again. But every single item of substance came from the attorney, not from the expert earning thousands of dollars for being there in court. The message to the jury was, the expert isn’t really the expert, and it is all really coming from the attorney. 

Leading an expert through parts of the direct examination is something that is done for efficiency and control – I get that. But attorneys can frequently put the goals of efficiency and control ahead of the goals of credibility, good communication, and persuasion. I believe that in most cases, leading your own expert is a really bad idea. In this post, I will discuss some of the reasons why, and I will share recommendations on good open-ended questions for your experts.

Why Not Lead? 

The attorney conducting the expert examination I describe above, I believe, simply thought that leading was the most efficient way to get all of the exact conclusions into evidence in the shortest possible time. I understand the motivation, but it is shortsighted: an efficient way to drain all credibility from your expert witness. As far as I know, leading the expert witness is generally allowed (e.g., see People v Campbell (1965) 233 CA2d 38, 44; Comment to Evid C §767) but judges will sometimes sustain the objection if the practice seems to be abused. Fundamentally, though, it shouldn’t be necessary. You put an expert witness on the stand because you want that witness to be understandable, believable, influential, and remembered. You want that expert to be a teacher. You don’t get there by leading.

I would say there are three good reasons not to lead your expert. 

One, it makes the expert appear to be a rubber-stamp for the attorney. The led expert doesn’t seem neutral, independent, or smart. 

Two, it disempowers the expert, creating within that person the feeling that they’re just there to agree with the attorney. A witness who feels passive and compliant might be somewhat okay in direct, but could be disastrous in cross. 

Three, it prevents the expert from being a teacher. The best experts are able to step outside the adversary frame, stylistically at least, and supply jurors with the kinds of useful and informative engagement that they remember from their best teachers in school. To do that, the witness has to be the one doing most of the talking.  

Alternatives to Leading: 

The way to get your expert talking and to serve as their proper role as experts is to ask open-ended questions.

  • What are you here to tell this jury?
  • What is the central issue you want to address?
  • Tell me how you got to your conclusion?
  • Why is that a fair method?
  • How does your approach give the other side the benefit of the doubt?
  • Do you have any criticisms of the other side?
  • How do you respond to the opposing expert’s criticism?
  • Why do you say that?
  • How do you know?
  • Can you break that down for the jury?
  • Can you show your work?  

Now, one big response to this from the litigator who likes to lead might be, “What if I can’t trust my expert to get the right stuff out, in the right way, and in the right amount of time?” But there’s a good response to that: practice. Go ahead and buy a few more hours of that expert’s time, sit down and finalize that direct examination outline together, thinking of it as a joint lesson plan, and then do as many live practice sessions as it takes for the testimony to come in clearly and persuasively without leading.


Other Posts on Expert Testimony: 


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September 5, 2016

Look for the Expert’s Mental Mistakes

By Dr. Ken Broda-Bahm: 


Witnesses make mistakes. And for the adversary, those mistakes can make for useful and entertaining cross-examination. We expect that to occur with fact witnesses who might be naive to the legal process and the attorney’s goals, but is there less opportunity to pounce on those mistakes when examining an expert? New research suggests that, in contrast, there might even be greater opportunity. The study (Greene, 2016) finds that subject-area experts are more rather than less likely to make mistakes about their specialty. Indeed, knowing a great deal about a subject doubles the risk of false memories about that subject. As reported in a review in Telegraphresearcher Ciara Greene from University College Dublin, looked at 489 subjects who were measured based on their interest in a number of topics (like politics, science, and sports) as well as their knowledge in those topics. Then they were given a list of four events, three of which were true and one of which was fictional. Having a high level of interest or knowledge in an area increased the chances of true memories, as we would expect, but increased the chances of false memories as well. One fourth of those responding reported a false memory within their area of greatest interest, and those who had significantly greater knowledge on a topic were nearly twice as likely to remember incidents about that topic that never happened. As Ciara Greene noted in LiveScience, “Most people are pretty confident in their own memory for events, but this research shows that false memory is a lot more frequent than many people realize.”

Social scientists have long been aware that false memories are common. But why would it be the case that expertise, in the form of greater knowledge and interest in an area, would correlate with more rather than fewer false memories? The author theorizes that such false-positives are the result of greater familiarity. In other words, new information, whether true or false, has a better chance of feeling familiar to the expert because it relates in some way to something that is already known. As the author told LiveScience, “This can result in a sense of familiarity or recognition of the new material, leading to the conviction that the information has been encountered before and is in fact an existing memory.” More knowledge means more possible connections and more possible mistakes. All of that means that experts are prone to error too, possibly more so. 

In my experience, many experts take their roles very seriously and prepare extensively even after years of experience. But some experts can take their expertise for granted and end up preparing less than necessary. Fact witnesses, after all, know they are in unfamiliar waters and respond by preparing. Some experts, in contrast, can feel like they have it down and have no particular need to study. And if they shoot from the hip, then they’re prone to the kinds of mental mistakes documented in the study. 

Of course, there are many checklists on the web which feature questions to ask the adverse expert in deposition. I want to focus on those that might tempt an expert to rely on their broad memory and thus have a relatively greater chance of leading to a mistake or failed recollection. Of course, testimony is not a quiz. But still, thorough questioning can provide a more complete picture and perhaps allow you to uncover a mental mistake or two. So this list may be useful in deposing the adverse expert or in preparing your own witness. These are general areas of questioning, and would need to be phrased to reflect the specifics of the case and the expert’s area.  

Training and Experience: 

  • What educational institutions did you attend during what time frames? 
  • What was your thesis or dissertation titles, methods, and conclusions? 
  • Have you won any awards or academic honors, prizes, or fellowships? 
  • What are the names and dates of past employment?
  • What professional societies currently list you as a member?
  • What licenses or certifications do you hold?   

Prior Publications and Testimony: 

  • Have you ever taken a position in conflict with your current testimony? 
  • Does your report list all publications in the last decade? 
  • Are any publications prior to the last ten years germane to your testimony today? 
  • Is there anything in these articles that you would now want to change or revise? 
  • How would you summarize your past publications? 
  • To what extent do you review literature that expresses a position contrary to the position you are taking today? 


  • Who made the first contact to retain you in this case, and what did you discuss? 
  • What advice or assistance has counsel given you as you completed your work in this case? 


  • Did you create a plan for research before you started? 
  • What literature did you rely on in creating a method? 
  • Can you summarize your method? 
  • Has this same method been used successfully in other contexts? 
  • Were there any aspects of this method that were abandoned? 
  • Are there questions that this method cannot answer? 
  • What data are you relying on? 
  • Can you summarize the data? 
  • What documents or data have you retained or discarded? 
  • Was there any data that was not used for this project? If so, why not? 


  • Are there any conclusions you explored and then discarded? Or, did you end up confirming every conclusion you set out to? 
  • What facts or data would need to be different for these conclusions to be shown to be wrong? 
  • How do you respond to critics of these or similar conclusions? 
  • Is there any further research that would be necessary to bring these conclusions closer to certainty? 
  • What is your own and your field’s standard for “reasonable certainty”? 


Other Posts on Expert Witnesses: 


Greene, C. (2016). “How interesting: Self-reported interest in a topic increases false memory.” Paper presented at the annual conference of the British Psychological Society’s Cognitive Psychology Section, Barcelona Spain.  

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March 31, 2016

Ask the Expert What Reasonable Certainty Means

By Dr. Ken Broda-Bahm: 

Certainty bricks

There comes a moment in each expert’s testimony where the actual opinions are delivered, and they’re always delivered with something like this build-up: “I can say to a reasonable scientific certainty that….” In physician malpractice cases, substitute the word “medical” for “scientific.” That is the legal standard, but what does that phrase really mean? And, particularly when an expert on the other side is using the same phrase to frame an opposite conclusion, how should a jury understand and apply it? The law doesn’t seem to give much guidance on this point, since the standard is required but not defined. So it is left to the experts themselves to come to their own understanding of what “reasonable certainty” means. And it should come as no surprise that there is some inconsistency in the ways different experts will understand that phrase. 

That is the conclusion of a recent study investigating what experts mean by “reasonable certainty.” A group of researchers from Penn State College of Medicine (Dias et al., 2015) surveyed 294 medical specialists who testify about head trauma in cases of suspected child abuse, and found a relatively high diversity of meanings that the experts apply. The researchers found that while there were some commonalities in the way the experts would operationalize that standard, there was a significant amount of variability as well. For the greatest number, “reasonable certainty” means a 90 percent chance or greater that the claim is true. But for other experts, reasonable certainty could be found at the level of 50 percent or even lower. The lead author, neurosurgery and pediatrics professor Dr. Mark S. Dias, commented in ScienceDaily that “The juries think that everybody’s testifying to the same degree of certainty, and that may not be true.” He continues, Knowing that one expert defines their degree of certainty as 98 percent and the other defines it as 50 percent would help the jury.” In this post, I’ll take a look at the study and share some ideas on how it can be applied to your preparation of your own expert as well as your cross of the opposing expert. 

The Research Findings: 

Three main conclusions standout from the study (Dias et al., 2015) on experts’ understanding of “reasonable certainty” in practice. 

A Lack of Comfort With “Reasonable Certainty”

Just 37 percent of survey respondents were comfortable with their own definition of reasonable medical certainty. That is understandable because this notion of there being a specific threshold for certainty is a legal concept, not a medical or a scientific one. Science and medicine tend to be recursive practices, relying on falsifiability: An explanation stands until it is overturned by new research. It isn’t simply treated as true once it reaches a specific threshold of certainty. 

One Shared Reference Point on What It Means

About half of the survey respondents felt that “reasonable certainty” boils down to a probability greater or equal to 90 percent. Of course, there is nothing magic about 90, compared to 80 or 95, except that it appeals to the common sense yardstick of “nine out of ten.” 

But a Lot of Variety in Other Individual Meanings

If about half say 90 percent or more, that means that about half say it means something else. Surprisingly, almost a third said that “reasonable certainty” means just “at least 50 percent.” Two percent used an even lower threshold. In addition, the researchers asked whether the “reasonably certain” diagnosis must also be the “most likely” possibility. The vast majority, 95 percent, said that it did, but 10 experts in the sample disagreed. More than a quarter of respondents also shifted their definitions depending on the situation – e.g., a different standard for criminal versus civil or family court. 

The Recommendations:

Given the variability of definitions, the question of what “reasonable certainty” means is one that should factor into your preparation for expert testimony.  

Discuss the Problem With Your Expert

Ask your experts what their own standard is for “reasonable certainty,” and how they would answer the survey questions. Expect that the legal standard is unlikely to match the medical or scientific standard they use on a day-to-day basis. Doctors, for example, operate based on probabilities rather than reasonable certainties. But the law will still require those magic words. In addition to being potentially unfamiliar, the percentage threshold might also be a little arbitrary. After all, in most cases the conclusion isn’t something that could be run through a simulator 100 times in order to see if it turns out correctly 90 of those times. At the same time, jurors will want a rule of thumb, and 90 percent is a meaningful number that at least seems to enjoy a narrow preference among experts. In addition to reporting the number, however, experts should also address the broader question likely to be on jurors’ minds: How do I know I can trust this conclusion? 

Expose the Problem With Their Expert

Given that more than a third of the surveyed experts expressed a discomfort with the concept of “reasonable certainty,” it is certainly worth probing the issue with the experts on the other side. You might find an expert who really hasn’t thought about it, who waffles, who is reluctant to put a number to their own concept of reasonable certainty, or who is inconsistent in defining the concept. The lack of certainty could undercut that expert’s credibility and reveal to the jury that there is no clear standard of what “reasonable certainty” means for this expert. As long as your expert has thought it through and has a better answer, it may be a useful approach to try with the opposing expert. 

We see it all the time in mock trials and real trials: Jurors distrust the advocates and the parties, and crave a neutral voice. The expert witness doesn’t quite fit that mold because jurors understand that the expert is hired and paid by one side or the other. At the same time, the expert’s methods should provide that air of neutrality, and part of that method is the standard of certainty that they’re applying. So it is worth it to ask. 


Other Posts on Expert Testimony: 


Mark S. Dias, Susan Boehmer, Lucy Johnston-Walsh, Benjamin H. Levi. Defining ‘reasonable medical certainty’ in court: What does it mean to medical experts in child abuse cases? Child Abuse & Neglect, 2015; 50: 218 DOI: 10.1016/j.chiabu.2015.10.027

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December 3, 2015

Address the Expert’s Earned Dogmatism

By Dr. Ken Broda-Bahm: 


“Earned Dogmatism” is a relative newcomer as an academic phrase, but it refers to the closed-mindedness that sets in once one dons the “expert” hat. While we like to think of experts as broad-minded, creative, and analytical, new research suggests that the “expert” label is more likely to induce a dogmatic mindset. This may have been what the famous industrialist Henry Ford had in mind: “None of our men are ‘experts'” he said. “The moment one gets into the ‘expert’ state of mind a great number of things become impossible.” A recent series of studies (Ottati et al., 2015) suggests that Mr. Ford was on to something. Discussed in an interview with National Public Radio’s social science correspondent Shankar Vedantam, the studies demonstrated that manipulating the self-perception of expertise causes changes in attitude, making the volunteers less open-minded.

The team, led by Loyola University’s Victor Ottati, administered tests to volunteers and made some feel artificially like experts by giving them an easier test. “Success on these tests puts the person in a position of temporarily feeling that they are an expert,” Ottati explained, “And then we noticed that the people respond in a more close-minded manner than the people who have recently just failed.” Apparently, the reason for that increased closed-mindedness is that a feeling of expertise boosts confidence. That, of course, is often a good thing, but it can also make people less willing to consider points of view other than their own — it can make them more dogmatic. While the study was conducted in the artificial setting of a lab, it is easy to see how its central findings can apply to experts in legal contexts as well. When one’s colleagues, clients, and courts bestow that title of “expert” on you, the resulting feeling of self-importance might create confidence rising to the level of arrogance. If the result is to make an expert more dogmatic, that mindset can be a liability when that expert is challenged by an adversary. This post takes a look at the opportunities for calling that out in the other side’s experts and for guarding against it in your own.  

Call Out Dogmatism in Their Experts: 

No one likes an arrogant expert. Being definite, confident, and certain are all good things for conveying competence. But being dogmatic, narrow, and inflexible can limit the credibility and usefulness of the expert. Of course, it can be a fine line between the two, and it is the role of opposing counsel to use cross-examination to pull the witness toward the latter labels. So when you’re examining an expert who might be prone to a bit of over-confident exuberance, call out the signs of that. What didn’t they do, consider, or review? Where are they unwilling to admit that they could be wrong, or to acknowledge that additional information could have led them in a different direction? 

In a previous post, I argued that one good and mnemonic way to think about it is to find the “Large Internal Error,” in the expert’s position: If it is large (significant), internal (based in the expert’s own methods/approaches/assumptions, not on outside critique), and an error (a mistake and not just a comparative disadvantage), then it hurts the expert. And it does’t necessarily have to be a critical or necessarily a material point, it just has to show that the expert is overreaching, or engaging in a little unearned certainty,  

And Avoid Dogmatism in Your Own Experts

The points above are, of course, staples of expert cross-examination. Showing that experts are too tied to their own opinions, too far away from neutrality, and too closed-minded can be a good way of showing that the expert witness is just another partisan and not a useful resource to jurors or the court. For that reason, avoiding the appearance of dogmatism in one’s own experts should be a staple of expert witness preparation. Here are a few bits of advice you can give your own experts. 

Practice Open-Mindedness

As you prepare and as you testify, remember that open-mindedness helps your credibility, and might also improve your testimony. For example, when you read the opposing expert’s report, don’t do so with an eye toward refuting it — at least not initially. At the start, you should read with an eye toward just understanding it. Once you can answer the question, “What would lead a reasonable person to this conclusion?” you are far better positioned to refute that conclusion in a way that will be useful and convincing to reasonable fact-finders.

Show Some Humility

Confidence is important, and part of that is certainty. But certainty doesn’t require that you present an impenetrable front. If you can show your human side while still retaining confidence, that is going to make you more likable and credible to fact-finders. That can mean admitting that the other expert is also qualified, or acknowledging a point against you that jurors are likely to see anyway. Also, you can show that you aren’t perfect in areas that don’t relate to your testimony, like the courtroom technology. 

Admit to Shades of Gray

Your conclusions should be as rock-solid as the evidence permits, but in the full context of your testimony, you should admit the unknowns, and acknowledge where different information would’ve led in different directions. One particularly good antidote to an overly dogmatic front is to say, “Here is how I would have concluded differently…” Knowing on what basis you could have reached a different opinion will help jurors see you as open-minded and dedicated to a process rather than to a dogmatic adherence to a prepackaged opinion. 

Remember that Your Process Matters More Than Your Conclusions

To jurors, the expert’s process is the most important part. They don’t watch an expert with the attitude of “Because this person is smart, I’ll accept their opinion.” In all likelihood, there is a person who seems just as smart on the other side with the opposite opinion. And fundamentally, jurors want to feel like they’re reaching their own conclusions. So like a good teacher taking a student through the steps, expert witnesses should be passionate and clear about the process they followed. It’s not a matter of being certain and unshakable on your conclusions as much as it is a matter of how effectively you can lead a jury to the same conclusions. 

In the NPR piece, Shankar Vedantam explains the problem with expertise: “People feel they have earned the right to close their ears and eyes to become dogmatic because they feel like they’re experts.” But if that expert wants to be effective and persuasive in court, the response should be the opposite. The open-minded teacher will always be the more credible expert. 


Other Posts on Expert Testimony: 


Ottati, V., Price, E. D., Wilson, C., & Sumaktoyo, N. (2015). When self-perceptions of expertise increase closed-minded cognition: The earned dogmatism effect. Journal of Experimental Social Psychology61, 131-138.

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