What is the test for denying a defendant's constitutional right to effective assistance of counsel?

inquiries of the defendant and of trial counsel that in the circumstances seem pertinent, it concludes that the defendant has made a colorable claim that he was denied his constitutional right to the effective assistance of counsel. A defendant has made such a colorable claim if he credibly establishes the possibility that his trial counsel failed to perform with reasonable competence and that, as a result, a determination more favorable to the defendant might have resulted in the absence of counsel's failings." (Jbid.; accord People v. Smith (1993) 6 Cal.4th 684, 693.)