Generally, document examiners state that a source signatures is needed to show that the signature on a document is cut from another document then pasted onto the document in question. In this case study, a technique is presented to demonstrate how a cut-and-paste was discovered without the source signature.
When she was a girl, the young woman had emigrated with her family to the United States from her home country in Africa. She grew up in the northeastern USA and was now attending college. As part of her application for United States citizenship she must present her birth certificate. Her father sent the birth certificate to her. The birth certificate had apparent alterations. Government officials refused to accept the birth as valid because her appearance did not match the age on the birth certificate. She was born in 1994 yet birth certificate appears to state her year of birth as 1984.
The decedent signed a life insurance beneficiary form a few weeks after having brain surgery. The plaintiff claimed the signature was not executed by the decedent. The defense claimed that the decedent had signed the document and the differences are attributed to the effects of brain surgery.
As with any other profession, document examiners have a range of expertise and experience. As important as it is for your client to make a clear assessment of your abilities, it is up to you to determine in advance, with a high degree of accuracy, whether the document examiner you plan to hire will perform the most accurate assessments and be ready to back up those assessments with a scientifically repeatable methodology in court.
None of us wants to feel that our opinions are tainted by bias. The ability to recognize when bias is an influence in an expert's opinion and the skill of an expert to overcome his or her biases is integral to an expert's credibility.