The purpose of conducting a forensic comparison of handwriting is to express an opinion, where the evidence is deemed to be sufficient, as to which of the following propositions the examiner believes the evidence supports

1. The writer of the sample material wrote the questioned material
2. The writer of the sample material did not write the questioned material.
   

In the initial stage of the process, the examiner makes a determination as to whether or not the questioned writing is similar or dissimilar to the comparison sample writing. Based on this determination all propositions are considered which could account for the observed similarities and/or dissimilarities. At the conclusion of the examination an opinion is expressed regarding the extent to which the evidence supports one of the two general propositions above.

Levels of opinion

1. The questioned handwriting sample was written by the writer of the comparison handwriting sample.
   This has been described as an opinion of ‘moral certainty’ on the part of the examiner.
   For some examiners this opinion level translates into ‘very strong support for the proposition that the questioned sample was written by the writer of the comparison handwriting sample.
2. There is strong support for the proposition that the questioned handwriting sample was written by the writer of the comparison handwriting sample.
   This opinion level is used when there is an identifiable limitation associated with the examination process.
   
3. No opinion can be expressed as to whether or not the questioned handwriting sample was written by the writer of the comparison handwriting sample. This is an inconclusive opinion.
4. There is strong support for the proposition that the questioned handwriting sample was not written by the writer of the comparison handwriting sample.
   This opinion level is used when there is an identifiable limitation associated with the examination process.
5. The questioned handwriting sample was not written by the writer of the comparison handwriting sample.
   This has been described as an opinion of ‘moral certainty’ on the part of the examiner.
   For some examiners this opinion level translates into ‘very strong support for the proposition that the questioned handwriting sample was not written by the writer of the comparison handwriting sample’.