Ninety-one percent of factually innocent defendants with prior records declined to testify compared to the 55 percent rate at which defendants with prior criminal records declined to testify in a four-county sample of criminal cases.
According to this study of those persons wrongfully convicted (and exonerated by DNA), 91% didn’t testify at their trial if they had prior convictions. But even 55% of those without a record didn’t testify. These are persons proven later on to be innocent yet they didn’t testify in their own defense. There is no correlation between trial testimony and innocence.