How fast is fluent handwriting?

When examining conventional pen-and-paper samples, forensic handwriting examiners evaluate writing speed by observing qualitative line features. However, technological advances that enable the digital capture of handwriting movements now allow for a quantitative analysis of time-related characteristics. This study aimed to determine the relationship between writing speed and the qualitative assessments of line quality in handwriting samples. Thirty-five hybrid handwritten samples (i.e., produced with ink on paper and simultaneously digitised) were created at average speeds ranging from 10 to 60 mm/s. High-resolution scans of these samples were distributed to experts worldwide, who rated their line quality as good, medium, or poor. A total of 94 responses were received and compared to the actual writing speed of the corresponding samples. The study demonstrated that poor line quality was most often assigned to samples below 20 mm/s, while good line quality assessments dominated those above 50 mm/s. A chi-square test confirmed that writing speed significantly influences line quality ratings. Spearman tests revealed a strong positive correlation between speed and "good line quality" ratings and a strong negative correlation between speed and "poor line quality" ratings. Nevertheless, the findings suggest that factors other than speed may also influence line quality. Overall, the results provide objective benchmarks for assessing handwriting fluency and have the potential for practical forensic applications.