What Does it Mean to Be an Expert Witness?
For those asked to testify as an expert witness, the title may be either flattering or a little scary. After all, what does it mean to be an expert? How do you become an expert? What sort of knowledge, experience, or other credentials does one need to be considered an expert for purposes of offering testimony in a legal proceeding?
Although the legal standard may vary among the jurisdictions, generally one can become an expert witness so long as they have unique and specialized knowledge that will assist the trier of fact in understanding the matters at issue in the case. We often think of expert witnesses as being the DNA expert in a murder case, or the specialized doctor in a personal injury case. But, there are many other instances where one may qualify as an expert witness, such as an appraiser testifying about the effect of a nuisance house on the property value of neighbors' homes, an engineer testifying about best practices in a construction defects case, or even an attorney testifying about what constitutes a reasonable attorney fee. As a result, virtually anyone with any form of specialized knowledge may be called as an expert witness in some instance.
The chief distinction between an expert witness and a regular, or “lay,” witness, is that an expert is allowed to offer opinions. Generally, witnesses are limited to testifying in a factual matter about things they have actually observed. Experts, on the other hand, may offer opinions on the facts of the case based on their specialized knowledge. Of course, an expert cannot trail off into conjecture or speculation. An expert's opinion should be based on direct observations, and should not be simply rubber stamping the opinion of the side for which it is testifying.
Moreover, because of the unique nature of an expert witness and the extra influence their testimony can have on the outcome of a case, they are also subject to additional challenges. One of the most common challenges to an expert witness comes in the form of payment. Many expert witnesses are professionals hired specifically because of their unique knowledge, but who have no other connection to the case. Obviously, this creates a strong potential for bias in the expert's testimony; a potential which is often realized.
As a result, it is almost a given that the fact that the witness is being paid for their testimony will be brought up at some point during the cross-examination. Of course, juries have become so accustomed to this that it does not have much impact anymore, but if you will be testifying, you should be aware that your compensation is fair game. As a result, it is usually best to simply answer questions regarding payment for testifying simply and calmly rather than using this as a rallying point to fight back against the opposing attorney. Doing so will simply emphasize the payment for testimony and could undermine any points you made for your side.
Another basis for challenging an expert's qualifications is his knowledge of the subject area and his method of reaching his opinions. Often, an expert's opinion may be challenged by reference to industry standards or common practices. Should the expert's opinion vary from those commonly accepted principles, they will be subject to intense scrutiny during cross-examination. This variance need not be either intentional or even true. Often attorneys will simply recast someone's opinion as being at odds with industry standards, forcing the expert to calmly stand his ground and explain his opinion. Just as the witness may be an expert in his field, an attorney is going to be an expert at turning the use of imprecise terms of speech against the expert.
The more complicated a concept is, the more room there is for the attorney to turn the vagueness of the English language against the witness. In fact, it is not uncommon for inexperienced expert witnesses to begin questioning their own findings or become belligerent with the attorney while on the stand. A skilled expert faced with this kind of verbal sparring will remain calm and will treat the attorney's often taunting, challenging questions almost like a petulant child in an elementary school class: by calmly pointing out the faults of the attorney's misinterpretation and steering the conversation back to the expert's correct analysis.
Expert witnesses are also treated differently in most jurisdiction in that they are often allowed to observe the testimony of other witnesses in order to offer rebuttal testimony. It is often said that parties in highly technical cases engage in a “battle of the experts.” In many ways, this can be very true in the trial, when one expert is allowed to comment on the methods and findings of another expert. Lay witnesses are usually not allowed to remain in court while other witnesses testify, but experts are often exempted from this rule. As a result, an expert needs to be prepared to spar with not just an attorney but also another expert. Obviously, careful preparation is key.
As you can see, much more goes into being an expert witness than simply offering opinions. It will be critical for any expert witness to not only form well reasoned, well thought-out opinions, but also to ensure that their attorney is well educated on these opinions, as well. Only by working closely will the presentation of the expert's testimony have the desired impact and effect on the case.
Disclaimer: While every effort has been made to ensure the accuracy of this publication, it is not intended to provide legal advice as individual situations will differ and should be discussed with an expert and/or lawyer.