To my fellow forum members, especially the experts on individuals' differences in handwriting --
I am a handwriting instruction/remediation educator. Hans-Leo Teulings suggested that I should ask here for information on the accuracy (or inaccuracy) of a common claim about handwriting.
In the USA, many handwriting teachers (and other people) very strongly believe that only one particular style of handwriting (cursive with all the letters joined) is capable of allowing the writer to have an individually identifiable signature.
Specifically, it is commonly denied that other styles (such as unjoined or semi-joined styles) produce individually identifiable signatures or,other individually identifiable writing: it is claimed that anything which is not 100% cursive (that does not join every letter, and so on) can easily be forged.
My own impression (from 25 years of experience and observation in handwriting instruction) is that their belief is incorrect and is without factual foundation. However, plainly it's important to have the advice of an expert (who will permit himself/herself to be quoted) rather than simply one's own experiences and impressions.
Can any reader of this message please provide any facts, observations, citable bibliographic references, etc., that address this question of whether different types of handwriting instruction/models do, or do not produce individually identifiable handwritings for their users? What is the relative difficulty of forging signatures (or other handwritings) across various styles: styles which use varying types of shapes, varying types and methods of joining, etc.?