What principle is handwriting identification based upon?

Handwriting identification relies on a pattern-based principle, which means that each individual has unique, identifiable characteristics in their handwriting. This includes aspects such as the slant, size, shape, and spacing of letters and words, which can all be analyzed to determine authorship. Handwriting is not random; rather, it reflects a person's habits and style, which remain somewhat consistent over time.

Forensic examiners look for specific patterns in the letter formations and writing style that distinguish one person’s handwriting from another. These patterns can indicate whether two samples of handwriting could have come from the same individual. In contrast, other principles such as randomness, frequency, and emotional connection do not adequately describe the basis for identifying and differentiating handwriting. Randomness would suggest a lack of consistency, while frequency and emotional connections do not play a significant role in the unique characteristics of handwriting that forensic experts analyze.