Learning the source of documents is important for a forensic document examiner to perform an effective examination. The source of documents is important for performing handwriting comparison. Unless request exemplars are obtained where the forensic document examiner observes a person executing writing on the documents, the forensic document examiner must make an assumption that the documents were written by the person whose name is on the documents.

Documents that are signed for legal purposes are usually good sources for exemplars. If the documents were signed in the presence of other people, this improves the legitimacy of the documents. Regardless of the circumstances, the document examiner can never be absolutely certain the known documents were really written and/or signed by the stated person.

The document examiner will request many exemplars that were written at different times and in different circumstances. The exemplars will be compared to determine whether the handwriting is consistent across the writings. If the handwriting across writings is consistent across writings, the chances it was executed by the same person is improved.

Similar writing should be compared with the questioned documents. This means that cursive writing is compared with cursive writing while printing is compared with printing. The same is true for all types of writing.

Signatures on legal forms are best for comparing a signature on a legal form. When comparing the signature on a contract or a deed, find signatures on other deeds, contracts, checks, driver’s licenses or other legal documents. For signatures on a personal letter or greeting card, try to find other signatures that were written on informal documents.

Known (Example) Documents must be authenticated. The reason is that the examiner needs to know that the writing or document against which the questioned documents are being compared are valid. This may require some research by the person who provides the questioned documents and the example documents to the document examiner.