Practice Tip: Use Motion Practice for Permission to Impeach an Expert

Consider using a pretrial motion to seek permission to impeach opposing expert witnesses with prior court opinions excluding their testimony.

In serial product liability litigation, the same expert witnesses often appear in multiple cases. If an opposing expert witness has been excluded in a prior case on Daubert or Frye grounds, can you get that information in front of the jury deciding your present case? The answer is maybe, and it's well worth a try. One possible approach is to file a pretrial motion seeking permission to impeach opposing experts during cross-examination with evidence of those court opinions. Here are a few arguments to consider in making such a motion.

First, evidence of prior exclusion may tend to suggest that the expert harbors bias against you or your client if the same parties and counsel were involved in the earlier proceeding. This is especially true if you have had several prior cases in which you have successfully sought the exclusion of the same expert. (Often this resentment is revealed in deposition testimony of the expert in subsequent cases.) Evidence that may suggest bias or prejudice on the part of the expert witness is almost always relevant to impeach the credibility of that witness, see, e.g., 39 A.L.R. 4th 742 (1985).

Second, even where there is no strong bias argument to be made, the admission of evidence of the expert's exclusion pursuant to Daubert or Frye should be allowed to impeach the expert witness's qualifications. A Daubert or Frye ruling disqualifying an expert on the grounds that his or her opinion is not sufficiently reliable is a conclusion that the expert is willing to render opinions without satisfactory scientific support, and is just as strong a basis for impeachment of expert qualifications as other evidence routinely allowed for impeachment, eg, the fact that an expert failed a board certification exam.

Finally, evidence of prior disqualification may be allowed if the expert witness opens the door by testifying that he or she relies on previous experience with the same product in “other cases.” Counsel should then be able to cross-examine him or her on the basis of the prior court decision(s) excluding his or her testimony from these “other cases.”

These examples are but a few of the arguments that can made to get evidence of prior opinions excluding the testimony of the opposing expert in front of the jury deciding your case. Remember that even if you have lost a Daubert or Frye challenge to the opposing expert witness in your present case, prior successes on that front may help you in your present case to discredit the expert, if you can find creative ways to get these prior rulings before the jury.

Consider using a pretrial motion to seek permission to impeach opposing expert witnesses with prior court opinions excluding their testimony.

In serial product liability litigation, the same expert witnesses often appear in multiple cases. If an opposing expert witness has been excluded in a prior case on Daubert or Frye grounds, can you get that information in front of the jury deciding your present case? The answer is maybe, and it's well worth a try. One possible approach is to file a pretrial motion seeking permission to impeach opposing experts during cross-examination with evidence of those court opinions. Here are a few arguments to consider in making such a motion.

First, evidence of prior exclusion may tend to suggest that the expert harbors bias against you or your client if the same parties and counsel were involved in the earlier proceeding. This is especially true if you have had several prior cases in which you have successfully sought the exclusion of the same expert. (Often this resentment is revealed in deposition testimony of the expert in subsequent cases.) Evidence that may suggest bias or prejudice on the part of the expert witness is almost always relevant to impeach the credibility of that witness, see, e.g., 39 A.L.R. 4th 742 (1985).

Second, even where there is no strong bias argument to be made, the admission of evidence of the expert's exclusion pursuant to Daubert or Frye should be allowed to impeach the expert witness's qualifications. A Daubert or Frye ruling disqualifying an expert on the grounds that his or her opinion is not sufficiently reliable is a conclusion that the expert is willing to render opinions without satisfactory scientific support, and is just as strong a basis for impeachment of expert qualifications as other evidence routinely allowed for impeachment, eg, the fact that an expert failed a board certification exam.

Finally, evidence of prior disqualification may be allowed if the expert witness opens the door by testifying that he or she relies on previous experience with the same product in “other cases.” Counsel should then be able to cross-examine him or her on the basis of the prior court decision(s) excluding his or her testimony from these “other cases.”

These examples are but a few of the arguments that can made to get evidence of prior opinions excluding the testimony of the opposing expert in front of the jury deciding your case. Remember that even if you have lost a Daubert or Frye challenge to the opposing expert witness in your present case, prior successes on that front may help you in your present case to discredit the expert, if you can find creative ways to get these prior rulings before the jury.