The main form of disqualification of an expert witness is dismissal due to conflict of interest.
Examples of Conflict of Interest:
- Attorney from the opposing side has communicated with the expert witness
- Expert accepts an offer from an attorney who was on the opposing side in a different case
- Attorney contacts an expert who testified for the attorney from the opposing side
Sometimes, there are implicit forms of conflict of interest. Confidential relationships occasionally do exist between an attorney and an expert from opposing sides. Thus, the court must take measures to determine if there has been:
- frequent interaction instead of one single contact
- formal confidentiality agreement
- excessive number of meetings between expert and attorney
- fraudulent documentation constructed by expert under sole direction of attorney
- monetary incentive to furnish expert answers/opinions
- disclosure of strategy to opposing party
Hence, conflict of interest is the main cause of disqualification. However, for some rare cases, an expert may be dismissed depending on the public interest in allowing or not allowing the expert to testify.