Saunders Christopher P, Davis Linda J, Buscaglia JoAnn
Document Forensics Laboratory (MS 1G8), George Mason University, 4400 University Drive, Fairfax, VA 22030, USA.
J Forensic Sci. 2011 May;56(3):683-9. doi: 10.1111/j.1556-4029.2011.01713.x. Epub 2011 Mar 10.
The proposition that writing profiles are unique is considered a key premise underlying forensic handwriting comparisons. An empirical study cannot validate this proposition because of the impossibility of observing sample documents written by every individual. The goal of this paper is to illustrate what can be stated about the individuality of writing profiles using a database of handwriting samples and an automated comparison procedure. In this paper, we provide a strategy for bounding the probability of observing two writers with indistinguishable writing profiles (regardless of the comparison methodology used) with a random match probability that can be estimated statistically. We illustrate computation of this bound using a convenience sample of documents and an automated comparison procedure based on Pearson's chi-squared statistic applied to frequency distributions of letter shapes extracted from handwriting samples. We also show how this bound can be used when designing an empirical study of individuality.
书写特征是独特的这一命题被认为是法医笔迹比对的关键前提。由于不可能观察到每个个体书写的样本文件，实证研究无法验证这一命题。本文的目的是利用笔迹样本数据库和自动比对程序来说明关于书写特征的个体性可以阐述哪些内容。在本文中，我们提供了一种策略，用于界定观察到两个具有无法区分的书写特征的书写者的概率（无论使用何种比对方法），并给出一个可通过统计估计的随机匹配概率。我们使用一个便利样本文件以及基于应用于从笔迹样本中提取的字母形状频率分布的皮尔逊卡方统计量的自动比对程序来说明这个界限的计算。我们还展示了在设计个体性实证研究时如何使用这个界限。
