Do the Dirty tricks of Cross-Exam Work on Experts


Underwood and Fortune observed that “one of the most common abuses of cross-examination takes the form of a question implying a serious charge against the witness, for which counsel has little or no proof. All too often, trial attorneys ask such questions for the sole purpose of wafting unwarranted innuendo to the jury box.” Kassin, Williams, and Saunders of Williams College published a fascinating mock jury study examining the effect of this tactic. Their study demonstrated that juror’s perceptions of an expert’s credibility were significantly diminished by a question implying a serious charge against the expert. This occurred regardless of whether the expert admitted the charge, denied it, or did not answer it due to a successful objection by the other lawyer.

In Kassin, Williams, and Saunders study, 105 mock jurors “read a rape trial in which the cross-examiner asked a question that implied something negative about the reputation of either the victim or an expert.” Kassin and his colleagues produced 7 versions of this trial - 3 in which the victim was asked a question implying she had accused others of rape in the past, 3 in which an expert witness for the defense was asked a question implying his work was poorly regarded by his colleagues, and 1 version in which neither witness was asked an accusatory question. In each version with an accusatory question, the witness either denied the implication of the question, admitted it, or did not answer the accusation because of a successful objection by the other lawyer.

After reading a trial transcript, each of the mock jurors individually completed a questionnaire without deliberation with other jurors. The jurors’ answers revealed that the accusatory question diminished their view of the expert’s credibility, regardless of the response. The effect was, of course, most significant when the expert admitted the truth of the accusation. But there was also a significant decline in perceived credibility even if the expert denied the accusation or did not answer it because of an objection. This effect occurred despite the fact that the jurors did not report accepting the implicit accusation as true. On the other hand, the accusatory questioning did not diminish the credibility of the victim unless her response was an admission. A denial on her part increased her credibility. A non-answer because of an objection increased it even more significantly.

Kassin, Williams, and Saunders observed: “From a practical standpoint, this study suggests that the use of presumptuous questions is a dirty trick that can be used to distort jurors’ evaluations of [an expert] witness’s credibility….judges should be aware of the dangers and make a serious effort to control alternative approach is to address the problem through cautionary instructions to the jury...perhaps jurors should be forewarned about the use of dirty tricks.”

But, of course, expert witnesses have no control over the questioning a judge allows. And, the dirty tricks experts encounter usually won’t be quite so dirty as to make a completely unfounded accusation against them. Most experts are more accustomed to encountering more run-of-the-mill twisting of their words. But still, this study is an interesting illustration of what always comes for an expert in a forensic setting - criticism. And hey, who knows, the criticism might actually be valid (let's hope it's not). But, even if the criticism is not valid, the jury still might buy into it. So what is an expert to do? Well, it starts with the way you present during your direct examination: 




Then, when cross-examination comes, don’t let the questions rattle you. Answer the questions, don't be evasive. You’re limited in cross-examination, but to the extent you can, teach there too. And then, of course, in your re-direct, teach, explain, give the jury really good information. Then, just move on and let the jury go through their own process and make their own decision.

Let’s return to what I said in my previous article based on the Ivkovic and Hans study: “Being clear, concise, and relevant, teaching the jury without jargon, and being pleasant - these are characteristics of a trustworthy expert, not an evasive one that's hiding something. So again, be engaging [be a good teacher], for as Ivkovic and Hans noted, ‘a good quality presentation may help to counteract problematic motives’ - or the perception of problematic motives, as the case may be.” Or, in this case, being an authentic, trustworthy, and helpful teacher may help to counteract the dirty trick of a false accusation implicit in a question, or any number of other slightly less dirty tricks experts may encounter. Make your peace with the simple fact that you don’t get to control how a cross-examining lawyer treats you and you don’t get to control how the jury responds. You do, however, get to control your own demeanor and approach.


  1. Underwood, R.H., Fortune, W.H., Trial Ethics, Boston: Little Brown, 1988.
  2. Kassin, Saul M., Williams, Lorri N., Saunders, Courtney L., “Dirty Tricks of Cross-Examination - The Influence of Conjectural Evidence on the Jury,” Law and Human Behavior, Vol. 14, No. 4, 1990.
  3. Ivkovic, Sanja Kutnjak and Hans, Valerie P., “Jurors’ Evaluations of Expert Testimony: Judging the Messenger and the Message” (2003). Cornell Law Faculty Publications. Paper 385.