The legal requirements for being an expert witness are fairly minimal. According to Federal Rule of Evidence 702, expert witnesses must have “knowledge, skill, experience, training, or education” which will “help the trier of fact to understand the evidence or to determine a fact in issue.” This is a very broad standard. Under this standard most adults could probably be qualified as an expert witness on something. A key role, if not the prominent role for an expert witness is to teach the jurist and jury, if applicable, on the evidence. By definition – the expert witness is testifying due to the fact that the matter at hand is not “common knowledge”. This teaching experience is very challenging in that:
- The expert witness is addressing an audience with variable levels of knowledge on the topic at hand;
- Too often the audience has a preconceived notion as to the evidence at hand. A working knowledge not an expert;
- Time. The testifying process is concise and very structured;
- The expert witness may find that immaterial facts are being utilized to distort the findings or opinion of the expert witness; and
- Be prepared for a counter expert. Clarke's three laws, including Clarke's fourth law: "For every expert there is an equal and opposite expert."