Zlotnick J, Lin J R
Department of Justice Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
University of Maryland School of Law, Baltimore, MD, USA.
Forensic Sci Rev. 2001 Jul;13(2):87-99.
In federal courts, the admissibility of scientific expert testimony in the last century has been governed by three major standards. The first of these standards, the "general acceptance" test, arose from the 1923 Frye v. United States (Frye) and required that any technique or method introduced in court be generally accepted by the relevant community of scientists. The more liberal "relevancy" standard of the Federal Rules of Evidence was enacted in 1975, and required the expert witness to be qualified by knowledge, skill, experience, training, or education. Finally, the "reliability" standard stated in the Daubert v. Merrell Dow Pharmaceuticals, Inc. (Daubert) opinion was handed down by the U.S. Supreme Court in 1993, supplanting the Frye general acceptance test as the sole determining factor in considering the admissibility of scientific expert testimony, and suggesting falsifiability, peer review and publication, and error rate as additional factors useful in evaluating a scientific technique. Changing views on expert testimony have also resulted in published criticisms of several forensic fields, especially those with subjective components. The first such field to be questioned, which also has been the subject of great debate, is expert handwriting identification. Challenges leveled against handwriting identification began with a law review article published in 1989 (and two subsequent articles); other challenges have been based on the requirements outlined in the Federal Rules of Evidence and Daubert. These challenges resulted in several court opinions with disparate views of handwriting identification, though testimony by an expert in the field was not rejected. In U.S. v. Starzecpyzel, handwriting evidence was admitted as nonscientific expert testimony under the Federal Rules of Evidence after failing a review under the factors outlined in Daubert. In U.S. v. Velasquez (Velasquez), the testimony of a document examiner was accepted, while the testimony of an expert critic of handwriting identification was rejected by the district court; however, on appeal, the Third Circuit held that both witnesses met the requirements of the Federal Rules of Evidence, and thus both testimonies were admissible. U.S. v. Jones (Jones) demonstrated yet another situation, where handwriting identification was challenged under Daubert. There the court found that because handwriting identification was never viewed as scientific evidence under Frye, it should not therefore be reviewed under Daubert. The Jones court admitted handwriting identification as nonscientific evidence, but stated that admissibility of nonscientific evidence should be governed by the facts of future cases. After some time and many other opinions on the admissibility of expert testimony under Daubert, several federal circuits permitted review of nonscientific expert testimony under the factors outlined in Daubert, while other federal circuits restricted such reviews only to purportedly scientific testimonies. In the latter arenas, determining whether handwriting identification was a scientific field or not had bearing on how it was reviewed for admissibility, if it was reviewed at all. This situation ended in March 1999 with the U.S. Supreme Court opinion of Kumho Tire Co., Ltd. v. Carmichael (Kumho), which held that the Daubert factors may be used for review of all expert testimony as the courts see fit, regardless of whether the field is considered scientific. In the wake of Kumho, two other cases challenged handwriting identification: U.S. v. Paul (Paul) and U.S. v. Hines (Hines). The Paul case, like Velasquez, dealt with exclusion of an expert critic of handwriting identification, and also like Velasquez, the court appeared to rely on the Federal Rules of Evidence rather than the factors outlined in Daubert to form its judgment. Hines, however, represented a significant departure from earlier cases, as handwriting identification was partially excluded in that the document examiner was permitted to testify to similarities and differences but was not allowed to opine as to the authorship. In sum, the federal courts are currently evaluating the admissibility of handwriting identification in a variety of ways. Though handwriting identification continues to be widely admitted as a form of expert testimony, the recent changes in admissibility requirements and challenges from the legal community have generated a climate where admissibility should no longer to be taken for granted. Because Kumho is a relatively recent case, its long-term effects on the admissibility of many fields of forensic science, including handwriting identification, are yet unknown.
在上个世纪,联邦法院对科学专家证言的可采性遵循三项主要标准。其中第一项标准,即“普遍接受”测试,源自1923年的弗赖伊诉美国案(弗赖伊案),要求在法庭上引入的任何技术或方法都要得到相关科学界的普遍接受。更为宽松的《联邦证据规则》中的“相关性”标准于1975年颁布,要求专家证人具备知识、技能、经验、培训或教育方面的资质。最后,美国最高法院在1993年下达了道伯特诉默克多制药公司案(道伯特案)判决书中所述的“可靠性”标准,取代了弗赖伊的普遍接受测试,成为考量科学专家证言可采性的唯一决定因素,并提出可证伪性、同行评审与发表以及错误率是评估科学技术时有用的其他因素。对专家证言看法的改变也导致了对几个法医领域的公开批评,尤其是那些具有主观成分的领域。第一个受到质疑的此类领域,也是引发大量辩论的主题,就是专家笔迹鉴定。针对笔迹鉴定提出的质疑始于1989年发表的一篇法律评论文章(以及随后的两篇文章);其他质疑则基于《联邦证据规则》和道伯特案中概述的要求。这些质疑导致了一些法院判决,对笔迹鉴定持有不同观点,不过该领域专家的证言并未被驳回。在美国诉斯塔泽克皮泽尔案中,笔迹证据在根据道伯特案中概述的因素进行审查未通过后,依据《联邦证据规则》被接纳为非科学专家证言。在美国诉贝拉斯克斯案(贝拉斯克斯案)中,文件检验员的证言被采纳,而笔迹鉴定专家批评者的证言被地区法院驳回;然而,在上诉时,第三巡回法院认为两位证人都符合《联邦证据规则》的要求,因此两份证言都可被采纳。美国诉琼斯案(琼斯案)展示了另一种情况,即笔迹鉴定在道伯特案下受到质疑。在该案中,法院认定,由于笔迹鉴定在弗赖伊案下从未被视为科学证据,因此不应根据道伯特案进行审查。琼斯案的法院将笔迹鉴定接纳为非科学证据,但表示非科学证据的可采性应根据未来案件的事实来决定。在经过一段时间以及关于道伯特案下专家证言可采性的许多其他判决后,几个联邦巡回法院允许根据道伯特案中概述的因素对非科学专家证言进行审查,而其他联邦巡回法院则将此类审查仅限于据称的科学证言。在后者的领域中,确定笔迹鉴定是否为科学领域对于其可采性审查(如果进行审查的话)方式具有影响。这种情况在1999年3月随着美国最高法院对锦湖轮胎有限公司诉卡迈克尔案(锦湖案)的判决而结束,该判决认为道伯特案的因素可由法院酌情用于审查所有专家证言,无论该领域是否被视为科学领域。在锦湖案之后,另外两起案件对笔迹鉴定提出了质疑:美国诉保罗案(保罗案)和美国诉海因斯案(海因斯案)。保罗案与贝拉斯克斯案一样,涉及排除笔迹鉴定专家批评者,并且与贝拉斯克斯案一样,法院似乎依据《联邦证据规则》而非道伯特案中概述的因素来形成其判决。然而,海因斯案与早期案件有重大不同之处,因为笔迹鉴定被部分排除,文件检验员被允许就异同点作证,但不被允许对笔迹归属发表意见。总之,联邦法院目前正以多种方式评估笔迹鉴定的可采性。尽管笔迹鉴定作为专家证言的一种形式仍被广泛接纳,但可采性要求的近期变化以及法律界的质疑营造了一种氛围,即不应再理所当然地认为其具有可采性。由于锦湖案是一个相对较新的案件,其对包括笔迹鉴定在内的许多法医科学领域可采性的长期影响尚不清楚。