Locating, Retaining, and Employing Effective Expert Witnesses

Locating, retaining, and employing effective expert witnesses can make or break a case.  As soon as it becomes evident a case will benefit from an expert witness, attorneys should start reaching out to colleagues looking for referrals.  It is rare for an attorney to conclude that they brought an expert witness in too soon. In fact, attorneys will frequently wish that they had brought an expert witness in sooner.  If you are a litigator, at some point you will need to consult an expert witness of one kind or another to fortify your case theory. It’s never too soon to start preparing.

The Importance of Opinion Testimony

Rule 702 of the Federal Rules of Evidence allows experts to provide opinion testimony if the following criteria are met:

  • The expert’s knowledge, be it scientific, technical, or other specialized knowledge, helps the trier of fact either understand the evidence or determine a fact at issue
  • The testimony is based on sufficient data or facts
  • The testimony is produced using reliable principles and methods
  • The principles and methods have been reliably applied by the expert to the facts of the case

According to the rule, an expert may be qualified based on knowledge, skill, experience, training, or education.  However, a combination of knowledge, skill, experience, training, and education generally provides testimony more weight than any one of these factors alone.

Note, the rules allow expert testimony in the form of an opinion to either assist the trier of fact to understand the evidence or provide the trier of fact with information that determines a fact at issue in the case.

Assist the Trier of Fact

Sometimes experts provide testimony that assists a trier of fact by providing information a juror may not otherwise have.  For example, how quickly can an 18-wheeler stop their vehicle? How does a full load impact the stop time? What if the road is wet?  Or there is an incline? Similarly, providing testimony about factors that increase or decrease one’s ability to accurately identify a potential perpetrator may inform the jury.  Finally, an expert may provide information on future medical bills, the amount of schooling necessary for job retraining, or the value of a family business. All of these provide information to the trier of fact which can help them evaluate the case, even though the testimony may not go to the ultimate issue.

Ultimate Issue

Often, however, the testimony of an expert can go to the “ultimate issue.”  By providing a court with known side effects of a particular combination of prescription drugs, an expert witness may provide the evidence needed to avoid a directed verdict.  An expert’s opinion about cause and manner of death may go specifically to meeting the burden of proof for one side or the other. Testimony about the generally accepted standard of care could be dispositive.

Cultivating a Stable of Witnesses

Lawyers who specialize in a given area, be it medical malpractice, forensic DNA evidence, or arson litigation, would do well to consider cultivating a stable of witnesses well in advance of any specific litigation.  By doing so, the lawyer has a Rolodex filled with potential witnesses available, both for initial case consultation and, in the right case, testimony.

Start by attending professional conferences attended by your target expert witness population.   Attend papers presented by experts who may meet your litigation needs. Take the time to observe the person presenting.  Consider it an audition. Pay attention to the following:

  • Grooming and dress
  • Communication skills
  • Ability to withstand scrutiny

Grooming and Dress

Take a moment to review their visual presentation.  This is how they dress when presenting to their peers, which means they aren’t likely to get more dressed up for your jury.  One’s presentation isn’t everything, but it is something. You’d be surprised how many experts think nothing of showing up in stained clothing, with uncombed hair, or in other states of disarray.  Unless you are willing to request your witness wear a suit and shave before court, only consider potential experts who have already demonstrated their affinity for good personal presentation.

Communication Skills

At this point, you are only evaluating an expert’s ability to project their voice to fill the room, maintain eye contact, use appropriate hand gestures, and the like.  Do they appear confident, or timid? In conveying their findings, are they dynamic or dull? People generally present information consistently. Will a jury find this expert captivating?  These are the questions you should seek to answer as you observe the expert in their natural habitat.

Ability to Withstand Scrutiny

For lawyers searching for experts, the best presentations include a question and answer session, wherein the expert’s peers are permitted to publicly question the findings.  Watch how the expert receives the questions challenging his or her work. Do they take on a defensive posture, or do they maintain a relaxed posture? Do they consider the points of the questioner, or reflexively defend without consideration?  Do they even listen to the question before starting to respond? One’s ability to defend one’s ideas, and consider the ideas of others, in a professional setting speaks volumes about how one may hold up on the witness stand.

Always Be On The Lookout

Never miss an opportunity to connect with a potential expert witness.  If you see someone who you think you’d like to put on the stand someday, make a point of introducing yourself.  Give them your card, and ask for one of theirs. When you get back to the office, send a quick email, reminding them of the meeting, and add a few words about what you enjoyed or found interesting or learned from their presentation. Ask them for a copy of their paper and make a note to yourself to reach out to them every six months or so to maintain the relationship.  Conducting a direct examination of a witness you have a history with is far easier than with a stranger.


While an ability to present well is important, proper credentials are critical.  Of course, given that knowledge, skill, experience, training, and education are all qualifiers for expert testimony, there is no one single formula that dictates the appropriate credentials.  However, there are some general guidelines. In almost any field, there is some educational program that may prove useful. From a Ph.D. in applied math to a hands-on training program, most disciplines have a “best practices” standard.  If you are uncertain of the standard, consider resources in the field. You can, of course, ask your potential expert – but don’t just take their word for it. Ask them to point you to the document in their field that deals with minimum education standards.


In addition to education, there is no substitute for experience.  However, “experience” may expand well beyond simply duplicating the experience of the expert on the other side.  Particularly in criminal cases, where the government relies on testimony from employees from the forensic laboratory, the defense may or may not be able to access similarly situated experts.  However, more than one type of experience may suffice. One does not need to be a bench analyst to understand the finer points of likelihood ratios, for example.

Prior Testimony

If an expert has provided prior testimony, this can be an advantage.  While every expert has to have a “first time” being qualified as an expert, it can be nerve-wracking to sponsor a first-time expert.  Those who have testified in the past should have a file readily available detailing prior instances wherein they were found by a court to be an expert, thus qualified to offer an expert opinion.


When considering an expert, consider their publications.  If they haven’t published, or if they haven’t published since their Ph.D. candidacy, ask why not.  Review your potential expert’s publications with an eye towards author order. In science, the order of the authors of a paper matters.  Generally speaking, the first author did the yeoman’s share of the work, with the second author still doing more work than the third, and so on down the line.  Review your potential expert’s publications. Are they consistent with your theory? Do they lend to your expert’s credibility?

Consider where your expert has published.  Publications in peer reviewed journals carry much higher weight than publications which are not subject to peer review. If you are uncertain whether a publication is peer reviewed, ask.  Similarly, letters to the editor are considered less prestigious than actual research, even if the letter to the editor calls into question the methods or conclusions of another person’s work.  Make certain you understand not only where your expert may have published, but the contents of their work.

Current Participation in the Field

Current participation in the relevant field is not necessary, but it can be helpful.  Where board certification is offered, such as forensic pathology, it may be helpful to have an expert who maintains their board certification.  However, if your expert is retired, or is currently in a job where maintaining certification is not required, such as supervising a forensic unit, or teaching at the university level, the lack of hands-on participation in the field is easily explained.

Communication Skills

Consider whether your expert can effectively communicate complex scientific issues in a manner the layperson can understand.  This level of vetting is different than observing their communication skills at professional conferences. At professional conferences, the chemical makeup of a given drug, or the impact of open versus limited slip differential doesn’t require a layperson explanation.  At trial, however, the ability to inform the trier of fact about complex or specialized details is critical to providing the foundations for an expert’s explanation of their work or their conclusions. If an expert can’t offer an explanation understandable to someone with an eighth-grade education, they are of no help to you or your jury.

Ability to Teach

Having the ability to teach is not the same as having a teaching position at a college or university.  Instead, the ability to teach is independent of other factors, although an ability to communicate complicated issues in simple terms is part of a good teaching ability.  Experts who are interesting, animated, and engaging to their audience accomplish far more than those who simply present their data.

If you are already well versed on an area of science or a technical matter, it is a good idea to bring in someone new to the subject matter while you first speak with an expert you are considering hiring.  Consider asking your paralegal, your secretary, or a fellow attorney to sit in as you ask the expert to explain a concept. Observe the teaching tools your expert relies on. Do they use stories? Analogies?  Do they use drawings to illustrate a point? Also, watch their energy level. If they are interested, excited, and vested in you understanding their information, they will probably show that same level of enthusiasm to the trier of fact.

A Good Expert Witness Can Settle Cases

Of course you want a good witness for your litigation.  However, you should also know that a good expert witness can eliminate trials altogether.  Once the other side deposes your witness, they may realize their exposure is greater than they previously presumed.  Having a confident, well qualified expert witness on your side often generates an offer to settle. This, of course, saves the client time, money, and the agony of the uncertainty of trial.


The power of having an effective expert witness cannot be understated.  Attorneys should proactively seek out potential expert witnesses, with an eye towards future use, both as consulting experts as well as potential testifying experts.  Consideration should be given to how experts present information, both amongst their peers and to lay people. Experience, prior testimony, publications communication skills, and the ability to teach should all be evaluated when looking to retain an exemplary expert witness.