All expert witnesses should be familiar with the standard jury instruction given by judges to jurors on expert witnesses.
It reads as follows:
JURY INSTRUCTION ON EXPERT WITNESSES
The rules of evidence normally do not permit witnesses to testify as to opinions or conclusions. There is an exception to this rule for “expert witnesses.” An expert witness is a person who by education and experience has become expert in some art, science, profession, or calling. Expert witnesses give their opinions as to matters in which they profess to be expert, and may also state their reasons for their opinions.
You should consider each expert opinion received in evidence in this case and give it such weight as you think it deserves. If you should decide the opinion of an expert witness is not based upon sufficient education and experience, or if you should conclude the reasons given in support of the opinion are not sound, or if you feel the expert’s opinion is outweighed by other evidence, you may disregard the opinion entirely.