Strickland v. Washington If prejudice is not shown, we need not seek to determine the validity of the allegations about deficient performance. Strickland v. Washington 466 U.S. at 697, 104 S. Ct. at 2069. The petitioner must show both deficiency and prejudice by clear and convincing evidence. See Tenn. Code Ann. 40-30-210(f). Since the creation of post-conviction procedures, the findings of the trial court in a post-conviction case have been given the weight of a jury verdict. See Janow v. State, 4 Tenn. Crim. App. 195, 200, 470 S.W.2d 19, 21 (1971). Our long-held standard of review on appeal bound us to the trial court's findings of fact unless we concluded that the evidence preponderated against those findings. Black v. State, 794 S.W.2d 752, 755 (Tenn. Crim. App. 1990). This traditional standard prevented us from reweighing or reevaluating the evidence or substituting our own inferences for those drawn by the trial court. Henley v. State, 960 S.W.2d 572, 579 (Tenn. 1997). Questions concerning the credibility of witnesses and the weight and value to be given to their testimony were resolved by the trial court, not this court. Id. This court has held that it would give due deference to the trial court's findings regarding the ineffective assistance of counsel under the well-settled standard set forth in Henley. Taylor v. State, 1999 Tenn, Williamson County (Tenn. Crim. App. July 21, 1999). While reaffirming the Henley standard for purely factual issues, our supreme court recently stated that "the issues of deficient performance by counsel and possible prejudice to the defense are mixed questions of law and fact" requiring a de novo review by this court. State v. Burns, 6 S.W.3d 453, 461 (Tenn. 1999).