Citing the ongoing need among forensic document examiners to strengthen the bases of handwriting comparisons, University of Central Florida researchers conducted an in-depth analysis of more than 1,700 cursive and hand printed specimens to develop an objective database of characteristics.
“This project is a statistical study, not a forensic study,” the researchers noted in a summary of their work. The NIJ-supported project was conducted by two forensic document examiners, a statistician, and a statistical standards expert. “Forensic document examination standards benefit by strengthening their foundations through the data from this project,” the researchers said. The database of handwriting characteristics can be part of an examiners “estimation of confidence” when making comparisons in a courtroom, they noted.
The researchers examined 880 cursive and 839 hand printed specimens that closely reflected the demographic proportions found in the United States. “The analysis of these specimens yielded numerous specific frequency occurrence proportions,” the researchers said. “Additional analyses have shown quantitatively the extent to which demographic features such as age, gender, ethnicity, education, locations of second/third grade training, and handedness impact the presence/absence of features.”
The researchers looked at hundreds of handwriting characteristics, including such things as enclosed loops, direction of strokes, up and down strokes, connections between letters, and the comparative height of letter peaks. In all, more than 900 characteristics were included in the analysis.
The purpose of the project was threefold. The first was to develop statistically valid frequency occurrence proportions of handwriting and hand printing characteristics based on samples from throughout the US. Next was to “provide practitioners of forensic document examination with a statistical basis for reliability and measurement validity to accurately state their conclusions.” Finally, the researchers wanted to “provide courts with the reliable data needed to understand the underlying statistical basis for the conclusions.”
One of the basic axioms of handwriting comparison is that no two writers utilize the exact same set of handwriting characteristics, the researchers noted. “The database created by this research and the resulting frequency occurrence proportions provides the forensic and judicial communities some empirical data concerning actual statistics with which to assess this axiom.”
The database provides a “baseline figure of distinctiveness for any cursive or hand printed entry,” the researchers said. But, they noted, “this project has just scratched the surface of the detail that is reviewed and is designed to give the user an appreciation of the probabilistic level of individuality in handwriting.”
They concluded by noting, “the forensic science community must now weigh the significance and use of the data in daily examination work.”
About This Article
The research described in this article was funded by NIJ cooperative agreement number 2010-DN-BX-K273, awarded to the University of Central Florida.
This article is based on the grantee report “Measuring the Frequency Occurrence of Handwriting and Hand-Printing Characteristics” (pdf, 85 pages), by Mark E. Johnson, University of Central Florida; Michele Boulanger, Rollins College; Thomas W Vastrick and Ellen Schuetzner, forensic document examiners.