The sequestration of expert witnesses falls under Arizona’s Rules of Evidence, Rule 615. ARIZ. REV. STAT. ANN. § 6-615 (2017). This rule requires that courts exclude a witness from the courtroom to not hear the testimony of other witnesses when requested by a party or on its own order. Id. The rule has five exceptions, and expert witnesses fall under the third. Id. The third exception is for “a person whose presence a party shows to be essential to presenting the party’s claim or defense.” Id. The courts can look to federal case law in situations that create confusion as to whether a witness should be excluded or not. Spring v. Bradford, 388 P.3d 849 (Ariz. Ct. App. 2017).