If there is a totality of similarity in all areas in two writings, and there is a sufficient quantity of writing, the conclusion that they were produced by one person is inevitable. However, what does it take to reach the opinion that there are two writers? The body of evidence necessary for an opinion that would eliminate a writer is not just diametrically opposite that necessary for an identification, but is generally more difficult to obtain. Theory has been espoused by other Questioned Document Examiners that a single unexplained significant and fundamental difference is a basis for elimination. This is simply just not so. The examiner must not limit his vision with blinders that allow him to see only one unidentified tree while standing in a pine forest.
While a single unexplainable difference between a questioned and standard writing must be something less than an absolute identification of the writer, it does not mean that the writing was authored by someone else. If you remember that identification is a compilation of total agreement and similarity between two writings then a single difference would not lead to an identification. However, the gray area of probability may be occasioned when there are some few differences uncovered by the examination, but still an expansive base of significant similarity. If the document examiner has the whole English language at his disposal, he need not limit himself to “yes”, “no”, or “I don’t know” opinions.
Among other factors preventing definitive opinions of identification may be that of a limited quantity of questioned material. One single letter or one or two numbers by themselves rarely exhibit the necessary quantity of individual characteristics needed for the examiner to conclude that nobody else in the world could produce the same pattern. A definite identification may likewise be precluded by a limited quantity of standard material. Here the questioned material may be a fair sized body of writing and the standard material simply one or two letters or one or two words which do not display enough of the letters and letter combinations present in the questioned writing.
Further, perhaps the questioned writing has been cursively written and the standards are in a hand printed form. There may be disguise in the questioned writing or there may be disguise in the standard writing. There may be a considerable difference in time between when the questioned writing was executed and when the standards were written. The submitter of document evidence should always advise the document examiner of any of the details that may impact upon the subsequent examination. Information concerning disparities in time, health conditions, drug (either legal or not) or alcohol use that may explain minor differences should be conveyed to the examiner.
As previously implied, one must be careful when making analogies between the science of Fingerprint Identification and that of Question Document Examination. While fingerprint examiners may have a specific number of “points of identification” which may be universally accepted within the discipline, the document examiner has no such index. A point of comparison in a latent fingerprint may be the ending or beginning of a piece of friction ridge (the lines in a fingerprint) or the intersection of two or more friction ridge lines. While these points are well delineated and may be easily seen by any number of other fingerprint examiners and interpreted as being the same “point,” the document examiner has no such well defined delineation of reference that will be easily recognized by another document examiner.
One document examiner’s “point” of comparison in a writing in question may be a small loop leading into a specific letter. Another document examiner may view that same area as two, three, or more points of identification by dividing the loop up into a loop entry area, loop exit area, etc. This process can be degraded until a “point” could theoretically be an extremely small line area or even a molecule of ink rather than the whole of movement that would form the piece of a recognizable letter. A questioned word may have 20 or 25 points of comparison to one document examiner and only two or three to another.
Often, an attorney either during a pre-trial conference or deposition will mistakenly refer to the markings on a Questioned Document Examiner’s working notes as “points”. This should be explained by the expert as nothing more than referenced areas that allow the examiner to refresh his memory by locating the similarities or dissimilarities of an examination at a later date.