What is the test for ineffective assistance of trial counsel on appeal?

To establish ineffective assistance of trial counsel on direct appeal, a defendant must show: (1) counsel's representation fell below an objective standard of reasonableness under prevailing professional norms; and (2) the defendant was prejudiced as a result. (People v. Lucas (1995) 12 Cal.4th 415, 436.) Prejudice is shown when there is a reasonable probability that, but for counsel's errors, the result of the proceeding would have been different. (Ibid.) "Reviewing courts defer to counsel's reasonable tactical decisions in examining a claim of ineffective assistance of counsel [citation], and there is a `strong presumption that counsel's conduct falls within the wide range of reasonable professional assistance.'" (Id. at pp. 436-437.) We reverse a conviction on direct appeal due to ineffectiveness of counsel only where the record of the trial itself, without regard to any other evidence such as declarations or affidavits from trial counsel, "`"affirmatively discloses that counsel had no rational tactical purpose for [his or her] act or omission."'" (Id. at p. 437.)