Social Science and Litigation, Part II 

 Professor Kousser鈥檚 1984 article on objectivity in expert testimony, which I first introduced to the blog  here , raises fundamental questions about the role of expert witnesses in litigation.  Among those questions is the following:  when presenting conclusions to a court, how much are expert witnesses entitled to rely on the adversarial process that is the foundation of lawsuits?  Some experts appear to believe that their job is to present the best statistical, engineering, chemical, or whatever, case for their sides.  Of course, they would not perjure themselves.  Still, such witnesses do not attempt to provide a balanced look at the factual information to be evaluated; rather, they focus on demonstrating how the relevant data can be interpreted in favor of the parties retaining them.  After all, the opposing sides have their own lawyers and, ordinarily, its own experts who (surely) are doing the same thing. 

 To make matters more concrete, I provide the following simplified example. My colleagues and I retained a quantitative expert in a redistricting case to measure the partisan bias of several proposed redistricting plans.  We used a measure of bias that assigned a score to each plan; a score of zero meant no bias, while a score of two meant roughly that the plan would give one party two 鈥渆xtra鈥? seats.  The (litigation) difficulty we ran into was that the scores did not appear to distinguish the plan we favored from the one the other side proposed.  The bias in our plan was, say, .03, while that of the other side was something like .15.  Thus, the difference in bias between the two plans was approximately one tenth of one seat.  But our expert, at our prompting, presented the results differently:  he emphasized the other side鈥檚 plan was five times more biased than our own. 

 Before dismissing this story, and the view of the expert as an extension of trial counsel, with a snort and a shake of the head about the lack of ethics in modern society, consider how the structure of the litigation process favors such choices.  At trial, an expert (just like any other witness) is not allowed to relate his or her views directly to the court. Rather, the expert speaks to the judge or jury only in response to questions from lawyers under the duty to advocate their respective clients' cases, that is, the duty NOT to be neutral.  Before trial, an expert who has consulted with a party to litigation may not be retained by the opposing party.  And trial counsel, not the witness, decides whether the expert speaks to the court at all. 

 There are good reasons for all of these rules.  The rule requiring testimony to come in response to questions from an attorney prevents witnesses from testifying about subjects deemed inadmissible (opposing counsel can object between question and answer).  With respect to the prohibition on consulting with one side and then working for the other, experts who have consulted for Side A learn about Side A鈥檚 case in a way that Side B might pay handsomely to discover.  But if, as many in the legal profession appear to believe, expert witnesses really are whores, could it be otherwise as litigation is presently structured?