Challenges to the Admissibility of Expert Testimony:  How Concerned Should Experts Be?

Life after Kumho

It was March 23, 1999, the day the Kumho Tire v. Carmichael decision was released by the U.S. Supreme Court. It was a day that would “live in infamy” for professionals who derived a large portion of their income testifying as expert witnesses.  The federal judge’s gatekeeping role defined in Daubert now was expanded to all expert testimony proffered under Rule 702- not just scientific testimony.

For the six years since the Daubert decision was handed down in 1993, many of those expert witnesses whose area of practice fell into the non-scientific realm had clung nervously to the hope, and sometimes even the prayer, that the foundations for their testimony and the methods they used to form their opinions would escape careful scrutiny by judge “gatekeepers.”

But Kumho was now officially the law of the land and the expert community was abuzz with questions.  “What would the implications be if I actually had my own opinions and methods challenged?  If I only testify in state jurisdictions, do I need to worry?  Are my methods truly sound?  How do I know?  Are others in my professional community being challenged?  If so, for what reasons and what have the outcomes of those challenges been?  If their methods were deemed insufficient, would I also become vulnerable to challenge and exclusion if I use the same methods?”

But the real subtext of all these questions and the ultimate issue was:  if my testimony were to be excluded, would my career as a testifier be effectively over?”


As a former testifying vocational expert myself, I had always been perplexed and even aghast at how little care expert witnesses seemed to give to justifying and supporting the legitimacy and “science” behind their methodologies. And I was equally perplexed by how little care attorneys gave to expert witness due diligence and to truly critically examining the professional backgrounds of both the experts they retained and the experts they opposed. Without really understanding or knowing for certain, it seemed to me the Courts were finally saying: “Enough is enough. We are no longer going to allow “trumped up” or illegitimate testimony to be heard by jurors. And you litigators better start being mindful and careful about which experts you select and you’d better make certain that their testimony meets Daubert criteria.

With the Kumho decision, the stars seemed to be coming into alignment for me from a philosophical and even an emotional standpoint and the timing was perfect. Since I had just a few months earlier started an internet-based medical-legal consulting company and was in the frame of mind to explore new ideas, I now had this Daubert/ Kumho idea kicking around in my head: what if there were a central online repository of all known “Daubert” cases. With such a product, expert witnesses would no longer have to speculate about what was “really” happening in the post-Kumho world and no longer have to rely on rumors and notoriously inaccurate scuttlebutt. Little did I realize at the time that this idea would have even more relevance, interest and utility for litigators who would look at such a resource as a critical underpinning of expert witness due diligence.

The challenge of tracking Daubert challenges

This last point I found to be very surprising. Didn’t lawyers have unlimited access to database products like those of LexisNexis and WestLaw? Wouldn’t information about Daubert challenges be front and center and relatively easy to locate through these sophisticated products? I soon learned that the answer was a resounding “no” and for several very important reasons. Here is why:

  • The issue of the unreported case. In 1999, the only significant databases of decisions and opinions concerning Daubert or any other issue of law- which were also widely available and accessible to litigators- were so-called “case law databases.”1 Keeping in mind that I was trained as a clinical vocational rehabilitation counselor and not as an attorney, I had little understanding of what case law really meant and that case law databases were largely comprised of published (or reported) cases- a distinction which at the time was nearly lost on me but which was soon to become perhaps the most important concept of my career as a Daubert Tracker. I quickly learned that the vast majority of decisions which trial judges render and the corresponding opinions they write (if they write an opinion at all) go unreported/ unpublished- including “Daubert” decisions. But while an unreported decision may have no “precedential” value, in the context of the expert witness due diligence, it has equal value in comparison to a reported decision.   It was inarguable that knowing whether an expert’s testimony had been previously challenged and/ or excluded would be vital information for a litigator. But unreported decisions at the time were exceedingly difficult to locate in spite of the fact that they represented the vast majority of decisions which judges made. The tedium and “pick and shovel” work required to gather unreported Daubert decision data gave the concept of a Daubert tracking product true commercial legitimacy.
  • Missing and inaccurate information in reported cases. I also soon learned that even in reported cases, the names of the challenged experts were missing completely or partially (first name and/ or middle name missing). For example, the deciding judge may write “The plaintiff’s accounting expert has presented an opinion without legitimate basis and is hereby excluded under Daubert.” The name of the excluded expert was not mentioned and needed to be located in order for the case to have any value to attorneys doing due diligence. Furthermore, judges often misrepresented the expert’s actual discipline, often referring, for example, to psychiatrists as psychologists or to economists as accountants. I found that in 30 per cent of all cases involving “Daubert” activity there was enough missing information about the expert in question that the cases would have no value from an expert witness due diligence standpoint. Locating that information would then give the case value to the expert witness researcher.
  • Boolean search issues. Crafting a Boolean search string which would accurately search through hundreds of thousands of cases in case law databases and identify truly relevant, on-point cases was not trivial. This is because the text of opinions often didn’t reference Daubert or Kumho at all. However, words like “unreliable” and “speculative” or concepts like “motion to exclude” or “lacking in foundation” were often indicators that there may have been Daubert activity earlier in a proceeding- just not clearly “spelled out” in the text of the opinion. A researcher needed to locate and examine underlying supporting documents to learn what actually transpired in the case. And at that time, virtually no supporting documents were online. So, in each such instance, a clerk of court had to be called and documents ordered. Or, one of the trial lawyers needed to be contacted.

These three issues alone made the aggregation of Daubert data a concept which was commercially viable, as without it important information would simply not be readily accessible to the legal research community.

But, additionally, I came to realize that there was an unintended consequence, if not benefit, of collecting and cleansing this enormous set of Daubert data: the value it would have in understanding trends, most vulnerable disciplines and methods and even the career implications for experts who have been excluded.

In the next edition of this magazine, I will begin to examine how Daubert has played out in practical terms from a career standpoint for testifying experts – including case studies of real life experts, from a variety of disciplines, who have been challenged and excluded.

  • 1Case lawis the set of existing rulings which made new interpretations of law and, therefore, can be cited as precedents. In some countries, such as the USA, the term is exclusively used for judicial decisions of selected appellate courtscourts of first instance, and other bodies discharging judicial functions. In other countries, such as most European countries, the term is applied to any set of rulings on law which is guided by previous rulings, for example, patent office case law. These interpretations are distinguished from statutory law which are the statutes and codes enacted by legislative bodies; regulatory law which are regulations established by governmental agencies based on statutes; and in some states, common law which are the generally accepted laws carried to the colonies and former colonies of England (USA, Australia, etc.). Trials and hearings which are not selected as ‘courts of first impression’ do not have rulings that become case law; therefore, these rulings cannot be precedents for future court decisions.[1] [2]
  • In law, an opinion (also consilia) is usually a written explanation by a judge or group of judges that accompanies an order or ruling in a case, laying out the rationale and legal principles for the ruling.
  • Opinions are usually published at the direction of thecourt, and to the extent they contain pronouncements about what the law is and how it should be interpreted, they reinforce, change, establish, or overturn legal precedent. If a court decides that an opinion should be published, the opinion is included in a volume from a series of books called law reports (or reporters in the United States). Published opinions of courts are also collectively referred to as case law, which is one of the major sources of law in common law legal systems.