In Beis v. Dias, 859 S.W.2d 835 (Mo. App. 1993), the defendant-physician testified as an expert witness. Id. at 838. The trial court excluded evidence that the physician had failed board certification and licensing examinations. Id. In holding that the trial court did not abuse its discretion in excluding the evidence, the court noted that "the defendant did not open himself to cross examination about failed examinations." Id. at 839-840.