Last update
Jun 18, 2009

Forensic Handwriting Identification Process

A forensic document examiner conducts scientific analysis on questioned handwriting and handprinting, to determine whether or not a particular individual is the author of a questioned piece of writing.

The identification of handwriting is a scientific process that includes the analysis of various aspects of natural writing, including the writer's slant, size relationships between letters, angles, connecting and ending strokes of letters, speed and flow of the writing, and formation of letters. Initially, when children learn to write, they are taught a set copybook pattern, the precise shapes of letters and relationships between letters. These traits are referred to as class characteristics, those features in handwriting that all individuals who learned that particular copybook style utilize. Over time, as writing becomes more of a natural process, and the writer no longer thinks about it, but does it automatically, he or she inserts individualized traits into the writing, much as one asserts his or her own personality. These traits are referred to as individual characteristics.

An examination of handwriting includes the analysis of an individual's class and individual characteristics. As a person writes over time, this combination of traits repeats itself, so one sample of an individual's writing can be compared to another. Consistent similarities can lead to an identification of common authorship, just as unexplainable differences can lead to an exclusion.

Upon receipt of a questioned signature or writing, the forensic scientist conducts various scientific tests, including examining the writing under magnification, to determine the individual and class characteristics of the writing. This same method is also used to study the known exemplars of the individual, to determine what the characteristics are, as well as the individual variation that all writers have. People do not always write exactly the same, but they do have consistent patterns that make it possible to determine the range of their variations in handwriting.

Questioned writings are then compared to the known standards, to determine if they have the same patterns of individual and class characteristics, without unexplainable differences. If the same patterns exist in both the questioned and the known exemplars, without significant differences, common authorship can be determined.

Handwriting examiners maintain reference libraries of known handwriting samples of both historical and contemporary famous people. Document examiners photograph all questioned material, and if it is identified, it is added to the reference library.