As an expert witness, your demeanor can be critical to how triers of fact view you, your report, and your testimony. Respect, politeness and composure can make a big difference in how the jury sees you. In "Effective Expert Preparation and Presentation," in The Advocate Magazine, May 2010, the Honorable Peter J. Polos (Ret.) writes that in addition to "Yes, sir/ma'am" and "Your Honor" that:Experts should not let their tempers show no matter how bad the behavior of the questioning attorney. If the expert maintains his or her composure and the cross-examining attorney does not, it can only negatively impact the other side. Some of the the worst expert testimony I saw was due to argumentative or defensive testimony by the expert on cross-examination.
I will add from a marketing perpective that word gets around among attorneys. If you are known as composed and well-mannered, you are more likely to be referred and recommended to other attorneys.
(Unfortunately, this article is not available online but I highly recommend you read the entire article if possible. Judge Polos has valuable advice on several areas of expert witnessing)
