Handwriting analysis as forensic evidence: reliability and challenges

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 safe ground to declare a document either spurious or genuine will be determined in each case. Consequently, investigation of as many of the characteristics and features as possible must be the best advice to anyone questioning the validity of any piece of writing."

Finally, Horswell (2004) adds that it would be foolhardy to go to court armed with insufficient examples of handwriting samples in an effort to persuade the trier of facts because this evidence will not be admissible. According to Horswell, "In order to make an accurate identification, sufficient handwriting must be available on which to base an opinion. This means that all questioned material is needed, as well as sufficient exemplars or known specimens."

Assuming a sufficient quantity of exemplars are available, the frequency of various handwriting characteristics becomes possible, again depending on the one-of-a-kind qualities of the handwriting and materials that are involved to demonstrate the principle of uniqueness for forensic applications.

In this regard, Evans notes that some undisputed examples of handwriting contained in a correspondence can include "the idiosyncratic manner in which the letter "e" [is written] for instance, almost in the Greek form, and a flattened out letter's and [a] habit of joining words together."

These idiosyncrasies, though, can be affected by illness or age. For instance, Evans points out that as people grow older, their handwriting can be profoundly affected due to increased frailty and shakiness.

Moreover, changes in handwriting can spontaneously occur, or they can erupt from time to time and over time in ways that defy forensic analyses. According to Evans (2004), "Like all other evidence, handwriting is identified on the basis of individuality. Children may be taught a specific way of forming letters, but they rapidly begin to inject their own quirks and idiosyncrasies. By the time a person reaches maturity, so the theory goes, his or her handwriting has acquired sufficient peculiarities so as to be identifiable. If only it were that simple."

In reality, forensic document examiners are faced with the entire constellation of human emotions expressed in handwritten form, and without context or sufficient samples, the analyses becomes difficult or even impossible in order to attain the level needed to satisfy a court of criminal law. In this regard, Evans emphasizes that, "In truth, our handwriting is rarely static. Fluctuations can occur, often from day-to-day. Mood, the position in which we sit, our physical well-being -- all of these can affect the way we put pen to paper."

It is these otherwise indiscernible deviations that help forensic document analysts confirm or refute the origin of handwriting samples. For example, Harrison, Burkes and Seiger (2009) report that, "Human beings are not capable of machine-like precision and repetition. As a result of the neuromuscular process, some variation in style (formation) is expected."

In fact, it is this variation from time to time and over time that is considered one of the essential aspects of the principle of uniqueness that is relied upon by forensic handwriting examiners. In this regard, Harrison and her associates add that, "Variation is an integral part of an individual's writing. It describes the changes and deviations, often minute that are found in repeated samples of one person's writing. More specifically, variation refers to the different way(s) that a writer makes each letter or character. This variation is normal and serves as an added factor to personalize and individualize writing."

An interesting case involving handwriting involved Sherlock Holmes' creator, Sir Arthur Conan Doyle. In the case of George Edalji, Doyle helped to exculpate an Indian national who had been convicted of mutilating and killing sheep, cows, and horses in 1903. The case attracted Doyle's interest and he helped prove, to the satisfaction of the court, that the anonymous letters written to the victims could not have been written by the defendant. A subsequent case that involved handwriting as forensic evidence was the infamous Lindbergh case. According to the World of Forensic Science (2012):

One of the first noteworthy cases in which handwriting analysis of this type was used was the 1932 kidnapping and murder of Charles Lindbergh, Jr., the infant son of aviation hero Charles Lindbergh. During the investigation, Lindbergh received fourteen notes from the kidnapper. Handwriting analysis later linked these notes to Bruno Richard Hauptmann, who was convicted and executed for the crime. (para. 2)

The forensic evidence provided the court in this seminal case is depicted in Figure 2 below.

Figure 2. Ransom note in the Lindbergh kidnapping case

Source: http://www.enotes.com/handwriting-analysis-reference/handwriting-analysisWorld of Forensic Science, 2006

A consistent theme that quickly emerges from the relevant literature, though, is that forensic document analysis is as much an art as it is a science and identifying the vagaries of the human condition as manifested in handwriting samples requires more than a casual examination. According to Evans:

To the accomplished examiner, there is, beneath these superficial deviations, a unique style that shines through, defying any attempt at disguise. It might be the angle of writing, its uniformity across the page, or the manner in which letters are formed, such as whether letters such as g and h are looped. Such analysis requires vast experience and a large investment of time before a considered opinion can be given.

Even the best criminals will be tripped up by their own idiosyncrasies when they try to forge someone else's signature. Despite repeated practices, the "real person" always seems to shine through to the trained forensic eye. For instance, according to Evans, "A forged signature presents very specific problems. Phony signatures based on memory tend to contain a combination of the forger's own writing habits and his or her recollection of the victim's habits. Often the discrepancies will be manifest."

This analysis, though, is complicated by the fact that people tend to vary their own writing from time to time and over time in ways the can defy even the best in the business, and the origin of the sample therefore assumes critical importance in establishing the identify of the writer. In this regard, Evans add that, "When the perpetrator makes a careful drawing of the victim's signature or traces an authentic signature, while the forgery may be exposed, identifying the perpetrator is next to impossible, since two individuals making careful tracings of the same signature can produce virtually identical drawings."

Despite these constraints, there are some innovations in technology that have been introduced in recent years that are making the analytical process more powerful than ever before in ways that contribute to its efficacy for use in evidentiary proceedings. For example, Evans reports that, "The latest weapon in the FBI's questioned documents arsenal is the video spectral comparator 5000 (VSC5000), an extraordinarily sophisticated imaging device that allows an examiner to analyze inks, visualize hidden security features, and reveal alterations on a document"

(see Figure 1 below).

Figure 1. Video Spectral Comparator

Source: http://mabsj2.wordpress.com/category/internship/

The video spectral comparator clearly has specific forensic applications for handwriting analyses, but it also has other applications as well. For instance, Evans (2002) reports that, "Using the VSC5000's infrared radiant energy source and filters, the examiner is able to see through inks to reveal objects that are obscured to the naked eye. But it has a variety of other uses."

By allowing evaluation of questioned documents at the minutest level, these innovations in technology are providing forensic examiners with new ways of confirming or refuting authorship of questioned documents. Indeed, Evans concludes that, "Such advances make the field of questioned documents one of the most dynamic in the whole forensic science arena."

In response to these innovations in technology, forensic examiners have developed standardized protocols for casework to provide the levels of results required by courts to establish evidentiary adequacy, beginning with a physical examination of the handwriting sample itself. For forensic applications, this step involves "close and careful scrutiny of surfaces and other items. Paper is the most typical surface examined."

During this initial phase of documentary analysis, forensic examiners focus on one or more of the following:

Something on the surface, such as handwriting, typewriting, alterations, or obliterations;

Something in the surface, such as indented writing, watermarks, or safety fibers;

Damage to the surface, such as torn edges, moisture, or charring; and,

Watermarks.

There are also two different approaches for determining whether the writing sample is indented or not: (a) side lighting (a light source is passed over the sheet of paper at an oblique angle), and (b) the electrostatic detection apparatus (ESDA) (this is an instrument that renders indented writing visible and provides a record of the writing).

The use of innovations in technology to facilitate the forensic analysis process has certainly not been restricted to the United States, though, and other countries such as Australia

and the United Kingdom have adopted these methods as well.

For instance, the Video Spectral Comparator 2000 is used for a variety of physical examinations of questioned documents for forensic applications in the United Kingdom including:

Determining the presence of indented writing;

Deciphering writing;

Rendering obscured writing visible; and,

Differentiating between inks and papers by their optical properties.

Other physical examination practices include:

Determining the contents of used carbon paper and typewriter ribbons,

Stabilizing and examining burned or moisture-damaged paper, and,

Reconstructing torn or shredded paper.

Modern forensic examiners are called upon to provide evaluations and comparisons of questioned documents including:

Samples of handwriting,

Hand printing,

Typewriting, and typewriter components including typewriter ribbons and elements;

Comparisons of photocopies, facsimiles, printers and printing processes;

Checkwriters, and,

Dry seals or stamps (rubber or similar types).

Protocols for a Typical Forensics Handwriting Case

Because all handwriting is unique in some fashion, every case involving forensics analysis will be unique. Despite these differences, there are some best practices that can be discerned from current methods used by the Federal Bureau of Investigation's questionable documents team for a typical handwriting comparison request.

The initial administrative procedures include the following:

1. Acknowledging receipt of the evidence;

2. Checking the evidence against the incoming communication (to ensure consistency);

3. Assigning unique identifying numbers to the submissions (denoting whether it is questioned or known); and,

4. Making arrangements for any other requested examinations such as DNA analysis or fingerprint comparisons.

Following the completion of appropriate documents reflecting all evidence submitted for analysis, the protocols call for preparing a scanned record as well. According to Held (2002):

"Typically, checks are side lighted for possible indented writing. The electrostatic detection apparatus is used only when specifically indicated."

Other steps used by the questioned documents unit at the FBI include those set forth in Table 2 below.

Table 2

Protocols followed by questioned documents unit at FBI for handwriting comparison requests

Step

Description

Preliminary analysis

Examinations of checks often begin with the identification and evaluation of the printing processes used. Are they consistent with one another and with genuine checks? If printing process anomalies are observed, the checks may be counterfeit. Other physical features of checks that interest document examiners are the safety features (watermarks), microprinting (usually in the signature line or as a border), and the type of checkwriter (if any) used.

Handwriting evaluation

The handwriting on the checks will be evaluated for suitability for comparisons. The known writing will be examined separately to determine whether it is original, comparable to that on the checks, and sufficient in quantity for viable comparisons. If these criteria are met, a side-by-side comparison of the questioned and known writing is undertaken

File searches

File searches for checks are conducted in the National Fraudulent Check File: always in the signature and company name sections, and, if applicable, in other specific portions of this file. Printing processes are sometimes searched in the Office Equipment File, and the Checkwriter File may be accessed, if applicable.

Source: Adapted from Held, 2002, p. 20.

In 1997, the Scientific Working Group for Questioned Documents (SWGDOC) was created in response to the growing demand for standardized protocols for forensic document analysis. According to Held, "SWGDOC's technical experts produce standards and submit them to ASTM International for ballot and eventual publication. ASTM is a voluntary standards development organization for technical standards for materials, products, systems, and services."

The ASTM Committee E30 on Forensic Science was established in 1970 and consists of 10 technical subcommittees, one of which is the E30.02 Committee on Questioned Documents. Each of the individual standards that is submitted to ASTM is subjected to a rigorous review process by forensic document examiners and other forensic practitioners, as well as other professionals who have a general interest in the forensic handwriting analysis discipline. This review process is intended to provide forensic examiners with unambiguous, concise, and high-quality standards.

To date, there have been a number of standards formally promulgated by the forensic document discipline through ASTM as set forth in Table 3 below (the two-digit number following the hyphen indicates the date of the standard and is the most current standard available).

Table 3

Current Standards for use by Forensic Document Examiners

Standard

Description

E444-09 Standard Guide for Scope of Work of Forensic Document Examiners

This guide describes the general duties and scope of work of forensic document examiners, also referred to as questioned document examiners, examiners of questioned documents, document examiners, or document analysts. A forensic document examiner makes scientific examinations, comparisons, and analyses of documents for purposes that shall aid the users of the examiner's service in understanding the examiner's findings.

E1422-05 Standard Guide for Test Methods for Forensic Writing Ink Comparison

This Guide is intended to assist forensic examiners comparing writing or marking inks. Included in this analysis scheme are the necessary tools and techniques available to reach conclusions as to the common or different origin of two samples of ink.

E1658-08 Standard Terminology for Expressing Conclusions of Forensic Document Examiners

This terminology is intended to assist forensic document examiners in expressing conclusions or opinions based on their examinations. The terms in this terminology are based on the report of a committee of the Questioned Document Section of the American Academy of Forensic Science that was adopted as the recommended guidelines in reports and testimony by the Questioned Document Section of the American Academy of Forensic Science and the American Board of Forensic Document Examiners.

E1789-04 Standard Guide for Writing Ink Identification

This guide covers assisting forensic examiners in identifying writing inks. Included in this analysis scheme are the necessary tools and techniques which have been successfully utilized to reach conclusions as to the common or different origin of two samples of ink.

E2195-02 Standard Terminology Relating to the Examination of Questioned Documents

This terminology standard includes terms that relate to the examination performed by forensic document examiners. The terms in the Terminology Section refer to typical copybook styles of writing and do not account for exceptional forms.

E2285-08 Standard Guide for Examination of Mechanical Checkwriter Impressions

This guide describes the equipments required and standard procedures for investigations that should be performed by forensic document examiners for examinations and comparisons involving mechanical checkwriters and their impressions (exclusive of rubber stamp checkwriter impressions or computer generated checkwriter impressions). These procedures, which are grounded in the generally accepted body of knowledge and experience in the field of forensic document examination, will depend upon the nature and sufficiency of the materials available. This guide, however, may not cover all aspects of particularly unusual or uncommon examinations.

E2286-08a Standard Guide for Examination of Dry Seal Impressions

The procedures outlined in this standard are grounded in the generally accepted body of knowledge and experience in the field of forensic document examination. By following these procedures, a forensic document examiner can reliably reach an opinion concerning whether two or more dry seal impressions have a common origin, or if a dry seal impression was created by a specific dry seal device.

E2288-09a Standard Guide for Physical Match of Paper Cuts, Tears, and Perforations in Forensic Document Examinations

This guide is intended for, but may not be limited to, physical match examinations of paper items. The physical matching or realignment of items of evidence may occur in two or three dimensions. The procedures outlined in this standard are grounded in the generally accepted body of knowledge and experience in the field of forensic document examination. By following these procedures, a forensic document examiner can reliably reach an opinion concerning whether or not two or more paper fragments were at one time parts of a single piece of paper.

E2290-07a Standard Guide for Examination of Handwritten Items

The procedures outlined in this standard are grounded in the generally accepted body of knowledge and experience in the field of forensic document examination. By following these procedures, a forensic document examiner can reliably reach an opinion concerning whether two or more handwritten items were written by the same person(s).

E2291-03 Standard Guide for Indentation Examinations

This guide provides procedures that should be used by forensic document examiners for examinations and comparisons involving visualization and recording of indentations.

E2325-05 Standard Guide for Non-destructive Examination of Paper

The procedures outlined in this standard are grounded in the generally accepted body of knowledge and experience in the field of forensic document examination. By following these procedures, a forensic document examiner can reliably evaluate the physical similarities or differences between papers that can lead to a determination as to whether papers originated from the same source.

E2331-04 Standard Guide for Examination of Altered Documents

The procedures outlined in this standard are grounded in the generally accepted body of knowledge and experience in the field of forensic document examination. By following these procedures, a forensic document examiner can reliably reach an opinion concerning whether a document has been altered.

E2388-05 Standard Guide for Minimum Training Requirements for Forensic Document Examiners

This guide provides minimum requirements and procedures that should be used for the fundamental training of forensic document examiners.

.Source: ASTM International at http://www.astm.org/

Finally, other recent standards that have been submitted to ASTM for voting and possible promulgation for use by forensic document examiners include the following:

Standard Guide for the Preservation of Charred Documents.

Standard Guide for the Preservation of Liquid-Soaked Documents.

Standard Guide for Examination of Handwritten Items for Simulation and Tracing.

Standard Guide for Classification of Facsimile Devices using Transmitting Terminal Identifier/Receiving Terminal Identifier (TTI/RTI).

Financial and Identification Documents.

Conclusion

The research showed that modern methods used for comparing handwriting samples are based on the principles that no two people write exactly the same and that certain writing characteristics tend to repeat in everyone's handwriting despite the fact that no one is able to write exactly the same way more than once. The research also showed that it is this combination of characteristics that is unique to every individual that is used by document examiners for handwriting comparisons for forensic applications. One of the harsh realities of life in the 21st century has been the loss of handwriting skills by young people who prefer digital interactions and interfaces. Many students are not even bothering to learn how to write in cursive, and handwriting may not even be around in a century or two. In the meantime, forensic document examiners will be called upon by criminal courts to help resolve questions concerning the authorship of questioned documents in ways that cannot be achieved otherwise. In the final analysis, innovations in technology will facilitate the analysis of documents for forensic applications, but humans will always be necessary to interpret these analyses in ways that are satisfactory to triers of fact in criminal cases where the outcome could involve life terms (in Australia) or capital punishment (in the United States).