chapter  4
Premises for the Identification of Handwriting
ByHeidi H. Harralson, Larry S. Miller
Pages 10

With respect to points of similarity in pattern-based evidence, there is a general misconception that exists respecting fingerprint examination. Handwriting may never permit precise determinations to be made of the value or significance of any particular writing characteristic or the probability of occurrence level for any combination of characteristics. Statistical inference, that is, statistical proof, underlies all scientific investigations in some manner and in order to be a scientific pursuit the identification of handwriting must, knowingly or unknowingly, engage statistical proof. The argument for the identification of handwriting is an inductive argument. Deduction is a matter of recognizing valid logical forms, but induction is a matter of weighing evidence. In the identification process, analysis and evaluation are the two aspects of the process that make formal training necessary, the personal presence of a competent teacher essential, and the accumulation of experience mandatory.