Research on the effects of signature size on experts' opinions

A signature is writing and/or signs that contain the signatory's personal characteristics and are used to indicate that people accept the authenticity of the formal and private transactions made by themselves in their daily lives and responsibilities arising from those transactions. If the documents are subject to forensic investigation and trial, forensic signature-examination experts are consulted to determine the identity of signatories. The experts reach an opinion at the end of their examinations and comparisons. But some issues affect the process of forming an accurate and reliable expert opinion about a questioned signature. In this study, the aim is to determine whether signatures differ across fields of different sizes and whether these changes affect examiners' opinions. Within the framework of the study, signature samples were collected using a signature form from a total of 60 volunteer participants who declared that they are healthy and who are at least high school graduates, between 19 and 65 years old, who are university and postgraduate students of the Institute of Forensic Sciences of Ankara University. The signatures in the smallest-sized boxes (2 ×0.5 cm) and the signatures on the larger-sized boxes, as well as the guidelines on the signature form, were compared and examined by the researcher according to 16 examination criteria using technical devices in a laboratory environment. In addition to the researcher, three handwriting and document examination experts examined the signatures on the signature forms. The data obtained from the study were analyzed using SPSS 20. The results show that signatures in the smallest areas exhibit significant changes in signature size, whereas criteria such as line quality, pen pressure, curls, and upward movements. Additionally, it was observed that the signature's size also influenced the experts' opinions. The Kruskal-Wallis test was used to assess whether the observed changes in participants' signatures and experts' views were associated with demographic variables, including gender, age group, and dominant hand. It was concluded that the initial movements of the signatures differed significantly according to the gender variable, and the pen pressure criterion differed significantly according to the dominant hand variable. However, no significant differences were observed in other criteria or expert opinions regarding the variables of gender, age group, and dominant hand.