A handwriting expert is someone who carefully studies and analyzes a person's handwriting. They can determine things like the writer's personality traits, emotions, and even possible forgeries of signatures or documents. Full definition
As part of my work as a forensic handwriting expert, I've studied more than 10,000 handwriting samples from people who work in a wide spectrum of professions and industries, including publishing. (bookpage.com)
A study was done that found that found handwriting experts are wrong 6.5 % of the time, which is pretty bad. (law.stackexchange.com)