Handwriting Expert Witnesses: Their Role, Value, and Admissibility

Determining who authored or signed a particular document can be a challenge.

Dani Alexis Ryskamp, J.D.

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— Updated on April 11, 2022

Handwriting Expert Witnesses: Their Role, Value, and Admissibility


While computer software has made it easier to tell when a word-processing file was created or modified by a particular machine, determining whether a handwritten item belongs to a particular writer remains difficult.

Enter handwriting expert witnesses, who specialize in helping attorneys settle questions about written evidence.

What Do Handwriting Expert Witnesses Do?

A handwriting expert witness can help determine who wrote a particular word or signature. They can also help settle questions about when a particular item was written down, using methods such as ink dating and analysis.

As expert witnesses, handwriting experts can analyze information, form opinions, and prepare reports in a similar fashion to other types of expert witnesses. Courts have accepted testimony from handwriting experts under both the Daubert and Frye standards.

Typically, a handwriting expert witness will first examine a questioned document to determine whether it contains enough of the subject’s handwriting to allow the expert to identify its unique characteristics. If so, the expert will seek to obtain another adequate sample of a subject’s handwriting. The expert compares the characteristics that appear in both samples and forms an opinion as to whether the document in question matches the known sample.

When Is a Handwriting Expert Witness Useful?

Handwriting expert witnesses typically do not state with certainty that a particular handwriting sample came from a particular individual, even if the goal of litigation is to prove that one person wrote a particular document. Instead, handwriting experts will express their opinion as to whether the characteristics of the handwriting on the document in question are consistent or inconsistent with the known sample used for comparison.

Nonetheless, the testimony of a handwriting expert can help bolster a claim that the questioned document was (or was not) written by a particular person, depending on which opinion the expert develops.

In some situations, a handwriting expert may also compare the words or phrases used in the two documents. For instance, in U.S. v. Crisp, the state’s handwriting examiner concluded that the questioned document (a note confessing to a bank robbery) was consistent with a sample of the defendant’s handwriting based in part on the fact that the word “tomorrow” was misspelled in the same way on both documents.

Handwriting experts may also have experience studying and testing various inks. These skills can help the expert form opinions as to when a document was written or signed, or whether two samples of writing were created with the same ink.

How Reliable Are the Methods Used by Handwriting Expert Witnesses?

The science of handwriting analysis is based on the presumption that no two people have identical handwriting. It assumes that because each person’s handwriting is unique, handwriting can be matched to an individual by examining subtle details and differences in writing, such as the shapes of letters, the pressure used, and where strokes are begun, ended, or joined.

Even courts that will accept a handwriting analyst as an expert witness may differ as to the nature and extent of testimony that is permissible from the expert in court. For instance, several cases in various jurisdictions have held that the expert may testify as to the similarities and differences between two handwriting samples, but may not state an ultimate conclusion as to the author’s identity, even if the expert feels confident he or she can make such as conclusion.

While not all courts have explained their reasoning, those that do tend to draw a distinction between the practice of identifying similarities and differences in handwriting characteristics and the act of drawing a definitive conclusion about identity therefrom. These courts have concluded that while the science of comparing handwriting samples meets the Daubert or Frye standard, the science of identifying individuals based on those samples has not.

Several courts have acknowledged the American Board of Forensic Document Examiners (ABFDE) as one appropriate accrediting organization for handwriting experts. The ABFDE was founded in 1977 “to establish, maintain and enhance standards of qualification” for handwriting experts and other forensic document examiners and “to certify applicants who comply with ABFDE requirements for this expertise.” The American Society for Testing and Materials (ASTM) also publishes standards for forensic document analysis, including handwriting analysis.

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