Section 66 - Competency of jurors

(1) A juror may not testify as a witness in the trial of the action in which that juror is sitting as a juror.

(2) Upon an issue of the validity of a verdict, a juror who participated in rendering that verdict may testify as any other witness, but the juror may not testify concerning the effect of a matter upon the determination of the verdict or concerning the mental processes by which the verdict was reached.

(3) Upon an issue of the validity of a verdict, a statement or an affidavit made by a juror who participated in rendering that verdict is not admissible to the extent that it concerns the effect of a matter upon the determination of the verdict or concerns the mental processes by which the verdict was reached.