Experts are a common feature of American litigation, for good, ill, or whatever. Here is a discussion of one's testimony on a common issue from a 10th Circuit opinion of August 7, Champagne Metals v. Ken-Mac Metals, Inc. in a state anti-trust claim about the effect of copyright infringement. The expert testified in an earlier opinion, Harold's Stores, to be discussed tomorrow.
"The economist testified that the defendant's illegal infringement on the plaintiff's copyrights didn't just do damage to [the plaintiff], it sen[t] a signal to anybody else that wants to enter this market, that if you come in here, you're going to get squashed because this big company will exercise its power and take your copyrights. In that regard, in economics, we would say it raised a barrier to entry. That itself is anti-competitive. That, in my judgment, is an unreasonable restraint of trade."