Mock Trial 101: How to Cross an Expert Witness
Wednesday, October 21, 2009 at 4:36PM The testimony of an expert witness can make a serious impression on the jury. The wise doctor with the wire rim glasses and the stoic engineer with the Harvard degree can bring a certain sense of credibility to an otherwise he-said-she-said legal debate. So then, it becomes your job on cross examination to do everything in your power to undermine the expert's credibility and testimony. Indeed, easier said than done!
Here are a few tips to help you navigate the dangerous waters of Expert Cross Examination
1. Preparation is everything: Unlike with most witnesses who may appear nervous on the stand or who way have difficulty recalling facts, a good expert witness is polished and knowledgeable of his/her testimony. To make matters worse, it is unlikely that you will have the time or means to become as fluent in the subject at hand. The best thing to do is read and summarize any depositions available to you from that expert. Even if the depositions are from a similar case involving the same expert. You might also look into his/her academic publications to make sure the testimony given in no way contradicts with his/her past published material.
2. Never decline the cross: Don't even think about letting the expert witness slide without cross examining him/her. If you do, the testimony is as good gospel. In other words, if you fail to cross examine the expert, it is likely that the jury will surmise that you have no rebuttal to the testimony and therefore it must be true.
3. Start with credibility: The vast majority of expert witnesses are getting paid to testify. Another small percentage are friends of the attorney or the attorney's client. You can almost guarantee that the witnesses has some level of bias and it is imperative that you call it to question.
Some examples of common questions that can be used to highlight bias:
a. Isn't it true that you were hired by attorney X to testify here today?
b. Isn't it true that you have testified on behalf of Exxon Mobile as an expert witness in over 35 trials in the past 4 months?
c. Isn't it true that you stopped teaching at Harvard in 2006 and have since worked as an expert witness in over 35 trials?
4. Qualifications: There is no such thing as the perfect expert witness. If you do your homework, you should be able to find one or two academic or professional shortcomings that you can play on during cross examination. For example, if the expert has a masters degree but not a Ph.D. it might be worthwhile to bring it up. Likewise, if the expert has published in other areas but not directly relating to the subject of his/her testimony, it can be effective to mention that as well. Try to get your hands on the expert's resume prior to trial in order to uncover qualification shortcomings.
5. Conflicting Publications: You can attempt to impeach the testimony of an expert witness by high lighting conflicting views from respected journals, books or other publications. The most effective way to accomplish this is by getting the expert to validate the credibility of a certain journal from which you intend to draw conflicting information. By doing this, you have essentially forced the expert witness to acknowledge that there are other credible sources that disagree with his/her expert testimony.
6. Flip the Script: In limited circumstances it may be effective to affirm portions of the expert's testimony. If you can ask effectively leading questions that limit broad answers from the expert, you can effectively use the expert as your own witness. In other words, by asking specific questions to which the expert agrees, you are giving the impression that the expert is in agreement with your side. Invariably the witness will see that you are attempting to box in his/her testimony with short questions. But if you can dominate the interaction and limit the responses to yes/no answers, then you will have shot at flipping the script on the expert witness. Check mate.
Reader Comments (1)
Yeah... This is good, but not really helpful for high school mock trials.