Is there a violation of the Sixth Amendment when a witness was excluded from the evidence?

In order to determine whether a Sixth Amendment violation occurred, it is necessary to make a two-part inquiry. Id. at 1549-50. First, we must inquire whether the excluded evidence is relevant. Id. at 1550. If the evidence is relevant, we ask next whether other legitimate interests outweigh his interest in presenting the evidence. Id. We will hold there is a Sixth Amendment violation only where the trial court abused its discretion. Id. "A trial court does not abuse its discretion so long as the jury has sufficient information upon which to assess the credibility of witnesses." Id.; Evans v. Lewis, 855 F.2d 631, 633-34 (9th Cir. 1988) (explaining that evaluation of witness' general credibility enjoys less protection than right to develop witness' bias).