Comparison of Document Examiners' Opinions on Original and Photocopied Signatures

Abstract

There is a lack of empirical evidence concerning document examiners’ ability to perform handwriting comparisons on photocopied writings. This study aimed to compare the accuracy of examiners’ opinions on 260 original questioned signatures and on the same signatures that had been photocopied. Six of the examiners from the Document Examination Section of the New Zealand Police participated in the study, which comprised two trials. Each trial was constructed according to the accepted process of comparing a group of known (specimen) signatures with a group of questioned signatures where the writer was known to the experimenters but not to the document examiners. One trial contained originals of the specimen and questioned signatures and the other comprised photocopies of the same specimen and questioned signatures. No errors regarding authorship were made for original or photocopied signatures, and there were no instances where an identification/elimination opinion was reversed between a photocopy and its original. Only 2.3% of opinions relating to an original signature differed in any way from that offered for its photocopy. The high correct rates for questioned genuine signatures were similar for original (100%) and photocopied signatures (98%). The correct opinion rate regarding the process of production of original and photocopied, simulated, questioned signatures combined was 99.7%. The results provide evidence that examiners are able to make comparisons on a complex signature with the same accuracy and similar sensitivity when using either originals or photocopies.

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