The primary objective of effective expert testimony is for the expert to present himself as a well-organized and credible person. The fact finders need not become experts as a result of the expert's testimony. They only need to be convinced that the expert is a believable person with something important to say and who will materially assist them in doing the job of deciding the case.
Whether the case is decided in support of the expert's position is not the true measure of the effectiveness of the expert's testimony. The true test of testimonial excellence is whether the expert is credible. The best opportunity the expert has to establish credibility is through direct examination.