Evidence establishing a conspiracy or collusion can be among the most challenging matters to prove in a Sherman Act case. The proof can take many forms, such as testimony from participants or cooperating witnesses, recordings, and documentary evidence. Often, the proof is based entirely on circumstantial evidence.
Another category of proof involves expert testimony based on economic analysis about whether the challenged conduct is indicative of a conspiracy or collusion or is anti-competitive. This article reviews the circumstances in which this type of expert testimony has been admitted and some of the primary challenges or objections to this form of expert testimony.