Jury instructions regarding expert witnesses in Virginia are outlined in Virginia’s Practice Jury Instructions §3:8. VA. PRAC. JURY INSTR. §3:8 (2017). These rules provide that when there is “serious conflict in the evidence” the jury must be instructed that it is responsible for determining how much weight to give each witness and which witnesses to believe. Id. However, the jury is not allowed to completely disregard testimony of a witness that “has knowingly testified untruthfully unless the court itself believes that willful false swearing has occurred.” Id.