The complexity of a handwritten signature is a key factor in the ability of forensic document examiners (FDEs) to determine whether a questioned signature is genuine or a simulation. Examiners are likely to offer stronger and more reliable conclusions in comparisons involving high complexity signatures. Comparisons of low complexity signatures introduce uncertainty and are likely to result in weaker conclusions or perhaps an opinion that the evidence is inconclusive regarding authorship. It is thus of great interest to explore the reliability and reproducibility of perceptions of signature complexity. This article reports on a study which collected signatures from 123 individuals and obtained subjective assessments of the complexity of the signatures on a three-point scale and a five-point scale from five FDEs. The degree of correspondence of the complexity ratings was evaluated by considering each pair of examiners separately. There was exact agreement on the five-point scale for about 45% of signatures and the examiners differed by more than one point on the five-point scale for approximately 9% of signatures. A statistical model treating the scores as continuous measurements estimates the intraclass correlation, the expected correlation of complexity scores from two different FDEs, at 0.65. Data on intra-rater reproducibility of complexity assessments was obtained by acquiring additional evaluations of complexity on seven of the signatures from the same FDEs. These data suggest the expected intraexaminer correlation of complexity scores aross the two occasions is 0.67, slightly higher than the interexaminer correlation. These results regarding repeatability and reliability of subjective assessments of complexity provide important information for researchers developing objective measures of complexity to enhance the signature examination process.

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评估手写签名的复杂性

手写签名的复杂性是法医文件审查员 (FDE) 确定被质疑签名是真实的还是模拟的能力的关键因素。在涉及高复杂性签名的比较中，审查员可能会提供更有力和更可靠的结论。低复杂性签名的比较会引入不确定性，并可能导致较弱的结论，或者可能认为证据对作者身份没有定论。因此，探索签名复杂性感知的可靠性和再现性非常有趣。本文报告了一项研究，该研究收集了 123 个人的签名，并从五个 FDE 中以三分制和五分制对签名的复杂性进行了主观评估。通过分别考虑每对审查员来评估复杂性评级的对应程度。大约 45% 的签名的五分制完全一致，审查员在大约 9% 的签名的五分制上有超过 1 分的不同。将分数视为连续测量的统计模型估计类内相关性，即来自两个不同 FDE 的复杂性分数的预期相关性，为 0.65。通过对来自相同 FDE 的七个签名的复杂性进行额外评估，获得了关于复杂性评估的内部评估者可重复性的数据。这些数据表明，两种情况下复杂性分数的预期内部相关性为 0.67，略高于检查者间相关性。