Efficacy of Handwriting Analyses as Forensic Evidence
Humankind has been writing for millennia, but it has only been in the last 100 years or so that individual handwriting samples could be distinguished by forensic document examiners to the extent that their testimony was deemed admissible as evidence in a court of law. In recent years, this analysis has been augmented by sophisticated handwriting analytical devices that are being used by national and international law enforcement authorities to identify clues that might otherwise go otherwise undiscerned. To gain some fresh insights into these issues, this paper provides a review of the relevant peer-reviewed and scholarly literature concerning the efficacy of handwriting analyses as forensic evidence, followed by a summary of the research and important findings in the conclusion.
Review and Analysis
Background and Overview
According to Black's Law Dictionary, forensics means "belonging to courts of justice."
The term forensics relates to criminal cases and is distinguished from forensis, which specially relates to civil matters "belonging to or connected with the court."
The examination of handwriting that is of questionable origin for forensic applications has been taking place for nearly a century now, and the testimony provided by handwriting experts is routinely accepted by courts of competent jurisdiction.
Despite these trends, the reliability of forensic handwriting analysts' courtroom testimony has also been challenged on numerous occasions.
These challenges typically assume one of two types: (a) the challenge that there is no basis for the premise that handwriting is unique to the individual, or (b) the challenge that the document examiners lack the expertise to assist the court.
The former challenge, uniqueness, represents one of the fundamental precepts of handwriting as forensic evidence, while the latter relates to the expert witnesses' credentials (which is beyond the scope of the instant analysis and is assumed). Therefore, the former challenge, the quality of handwriting as forensic evidence, is discussed further below.
Handwriting as Forensic Evidence
Whether it is elegant and graceful or angry and cribbed, handwriting is a complex process that involves a wide range of factors. For instance, Harrison and Seiger (2009) report that, "Handwriting is a complex motor skill that is the combination of sensory, neurological, and physiological impulses. Factors such as visual perception and acuity, comprehension of form, central nervous system pathways, and the anatomy and physiology of the bones and muscles of the hand and arm all combine to produce the desired output."
These factors remain as salient for handwriting acquisition in the 21st century as well. Indeed, the beautiful illuminations that were created in medieval scriptoria were based on the same rote learning processes that characterize handwriting acquisition today. The important point for handwriting analysis for forensic applications, though, is that everyone acquires this ability differently based on the unique combination of all of the foregoing factors and others that elude quantification. According to Harrison and Seiger (2009), "Most people learn to write by copying letter formations from a copybook at a young age. The ability to reproduce the letter formations varies from one person to the next and is based on each writer's perception of the image and his or her ability (motor skills) to reproduce that visual perception. The act of handwriting is mastered through practice and repetition."
Like soldiers and firefighters that react to life-threatening dangers by running towards them rather than away from them because of their discipline and training, it would seem that once acquired over time, people's handwriting also becomes unique over time through training despite conscious efforts to conceal or alter it. For instance, Burkes and Seiger add that, "Once [handwriting is mastered], writers focus on the subject matter rather than the physical act of writing and deviate from the copybook forms, interjecting their own individual characteristics. The writing becomes a pattern of subconscious, habitual formations that are repeated from one writing to the next (emphasis added)"
It is this unique quality of handwriting that forms the essence of forensic handwriting analysis. In this regard, Harrison and Seiger (2009) report that, "The comparison and evaluation of these individual features or habits enable forensic document examiners to identify or exclude, if possible, a known writer as the source for any questioned writing."
It is commonplace for even young people to be able to distinguish handwriting samples intuitively (when receiving passed notes in class, for example), but the ability to distinguish one writing sample from another, or to match samples, requires a far higher level of acuity for forensic applications. For example, according to Harrison and Seiger (2009):
Lay people may recognize the handwriting of an individual and differentiate between individuals to some degree; however, they observe only the gross features of the handwriting, such as letter formation, size, or slope of the handwriting. Lay people typically do not consider the subtleties in the writing that may differentiate it from other very similar writing.
Criminal courts, though, demand a far higher level of analysis than lay examination can provide and document examiners performing analyses for forensic applications must be able to distinguish far less obvious writing elements. The handwriting features that are most frequently examined by forensic examiners include the following:
1. The size and slope of the writing,
2. Pen pressure;
3. Pen lifts;
4. The spacing between words and letters;
5. The position of the writing on the baseline (the position of the character in relation to the ruled or imaginary line);
6. Height relationships;
7. Beginning and ending strokes; and,
8. Line quality.
For the purposes of forensic applications, there may be a need for a number of writing samples in order to confirm or refute identify, a luxury that may not always be available. In this regard, Harrison and Seigel also point out that, "A writer's identity cannot be established through a single individual feature in the writing. Rather, identity is established through a combination of the significant features between the writings, with no significant differences."
There are some ways to defeat many forensic analytical techniques, though, and as criminals use innovations in technology to their advantage, the analysis of handwriting samples becomes even more complex. In this regard, Harrison and Seigel (2009) emphasize that, "Not all handwriting is identifiable. For example, when a person traces another individual's signature, that person imitates the writing habits of the original signer, and therefore, the imitator's own handwriting characteristics are not manifested in the tracing."
Nevertheless, forensic analyses can provide some valuable data about a handwriting sample, For instance, Harrison and Seiger (2009) note that, "The forensic document examiner would be able to identify the writing as a tracing and associate the writing back to the model signature, if available, but would not be able to identify the writing with the person who traced the signature."
Like the lawyers' "but for," the principle of individuality represents the foundation of the forensic application of handwriting analyses today. In this regard, Harrison and Seigel report that, "The principle of individuality, also known as the principle of uniqueness, forms the basis for handwriting analysis. That is, no two writers share the same combination of handwriting characteristics given sufficient quantity and quality of writing to compare."
The principle of uniqueness is not restricted to handwriting analyses, but rather extends to all areas of criminal investigation. For instance, according to Turvey (2002), "Individuals develop uniquely over time, in response to biological, environmental, and subsequent psychological factors. However, similar in their past and present, no two people will develop in precisely the same fashion."
Indeed, studies of handwriting differences between identical twins have shown that although their handwriting is similar (sometimes incredibly so), they still manifest unique differences in their handwriting that can be discerned through careful forensic analyses. As Turvey (2002) points out, "This is because individuals are born with their own unique genetic profile and temperament, are raised into their own culture surrounded by other uniquely formed individuals, and develop their own unique constellation of associations with respect to pleasure, pain, taste, and distaste."
In his seminal work, Questioned Documents, Albert S. Osborn (1929) elucidated the principle of individuality as it relates to handwriting: "The amount of writing must necessarily always be considered, but total coincidence of all characters is so remote that even identity of a small amount of writing is very improbable."
Therefore, when it comes to developing valid cases based on forensic analyses of handwriting samples, another dictum is that the more samples that are available for analysis, the better. In this regard, Horswell (2004) emphasizes that, "All questioned documents involved in a particular investigation should be submitted to the laboratory for examination. This is important since questioned documents are identified by a comparison of similarities, plus an absence of divergences or dissimilarities."
Likewise, Cox and Wallace (2002) also emphasize that when it comes to handwriting samples for forensic applications, "the more the better," but these authorities also add that every case is also unique. For instance, Cox and Wallace (2002) point out that, "How much evidence must be amassed to put the investigator on…