How can an expert provide an opinion on a signature?

An expert can provide an opinion on a signature by comparing the disputed signature with a genuine specimen signature. This method is fundamental in forensic document examination, where the authenticity of a signature is often established by direct comparison with known, authentic signatures of the individual in question. In this process, the expert looks for consistency in various features, such as stroke patterns, pressure, spacing, and overall style, which can help determine whether the signature in question is genuine or forged.

This comparison serves as the primary basis for an expert's opinion because it relies on empirical evidence and established forensic techniques. The expert's ability to identify specific characteristics that match or differ between the signatures plays a crucial role in arriving at a conclusive determination regarding authenticity.