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Michael J. Allen

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Herausgeber: John Wiley & Sons
Kategorie: Wissenschaft und neue Technologien
Serie: Essential Forensic Science
Sprache: Englisch

Beschreibung

Forensic document examination is a long established specialty and its practitioners have regularly been shown to have acquired skills that enable them to assist the judicial process. This book, aimed primarily at students studying forensic science and document examination in particular, introduces all of the essential ideas that are to be found in the work of the forensic document examiner in a concise and straightforward way. Each examination type is described not only in terms of its procedural basis but also the science and reasoning that underpins it. The reader will be able to relate the different kinds of interpretation skills used by the document examiner to those used in other forensic disciplines.

This book will be an invaluable text for all students taking courses in Forensic Science or related subjects. The book will also be a useful reference for researchers new to this field or practitioners looking for an accessible overview.

The author will be adding new references that are relevant as they are published and some more worked examples from time to time. Please visit http://qdbook.blogspot.co.uk/ for more details.

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Leseprobe

Cover

Series Page

Title Page

About the Author

Series Foreword

Essentials of Forensic Science

Preface

What is document examination?

Purpose of this book

Structure of this book

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Guide

Cover

Table of Contents

Series Foreword

Preface

Begin Reading

List of Illustrations

Chapter 2: Handwriting Development and Comparison

Figure 2.1 A similar pen path is used for writing the letter

and the letter pair

Figure 2.2 Handwriting from same person using accustomed and unaccustomed hand.

Figure 2.3 Handwriting with clockwise and right to left t-crossbar (left-hand example) and anticlockwise and left to right t-crossbar (right-hand example).

Figure 2.4 Examples of national handwriting characteristics (see text).

Figure 2.5 The tip of a ballpoint pen (x8 approx.).

Figure 2.6 Striation lines in a ballpoint pen ink line (x10 approx.).

Figure 2.7 A felt tip pen nib (x8 approx.).

Figure 2.8 Various letterforms (see text).

Figure 2.9 Worked example: Anonymous note.

Figure 2.10 Worked example: Sample of handwriting.

Figure 2.11 Worked example: List of music albums.

Chapter 3: Signature Examination

Figure 3.1 The upper signature has a smooth pen line with variation in pen pressure. The lower signature is a freehand simulation showing a shaky pen line and a ‘drawn’ appearance.

Figure 3.2 The tracing lines are close to, but not exactly overwritten by, the ink line.

Figure 3.3 A scanned and printed signature overwritten in ink.

Figure 3.4 Five naturally written specimen signatures compared to (i) a genuine signature written at about the same time; (ii) a genuine signature written many years earlier; (iii) a disguised signature written by the true signatory; (iv) a memory copy; (v) a freehand simulation.

Figure 3.5 Worked example: Agreement.

Figure 3.6 Worked example: Specimen signatures.

Chapter 4: Documents Produced Using Office Technology

Figure 4.1 The arrangement of typebars.

Figure 4.2 Two characters are present at the end of each typebar with the upper one accessed by using the shift mechanism (x3 approx.).

Figure 4.3 Letter

in a font with (left) and without (right) serifs.

Figure 4.4 Paper inserted round a typewriter platen.

Figure 4.5 Close up of letter

showing the weave pattern from the fabric ribbon (x15 approx.).

Figure 4.6 Close up of a carbon copy.

Figure 4.7 Close up of a letter

with top and bottom serifs on left side damaged (x15 approx.).

Figure 4.8 Close up of an infilled letter

(x15 approx.).

Figure 4.9 Showing a printwheel with one character at the end of each spoke (x2 approx.).

Figure 4.10 Close up of a severely damaged letter

on a printwheel (x10 approx.).

Figure 4.11 A carbon film ribbon showing readable text after use.

Figure 4.12 A lift off correction ribbon with removed characters present.

Figure 4.13 Matrix characters are made up of a pattern of dots (x15 approx.).

Figure 4.14 Letter

printed with a laser printer showing the molten appearance of raised toner on a paper surface (x30 approx.).

Figure 4.15 Close up of a group of drum defects (x15 approx.).

Figure 4.16 Close up of a colour laser print showing four colour (showing as shades of grey) dots (x30 approx.).

Figure 4.17 Close up of inkjet printing with ink absorbed into paper (x30 approx.).

Figure 4.18 Worked example: Note item 1.

Figure 4.19 Worked example: Note item 2.

Chapter 5: The Examination of Printed Documents

Figure 5.1 (a) The symbol on the front of the currency note; (b) the symbol on the reverse of the currency note; (c) the currency note viewed with transmitted light giving the completed symbol (x4 approx.).

Figure 5.2 Close up of a half tone image showing how shades of grey are created by different densities of printed dots (x30 approx.).

Figure 5.3 A letterpress printing surface (x25 approx.).

Figure 5.4 Ink squash around the edge of printed characters (x25 approx.).

Figure 5.5 Stamp impressions vary in appearance depending on different conditions of applying. The upper stamp impression has been applied more heavily than the lower impression.

Figure 5.6 The gradual merging of colours found in split duct printing.

Figure 5.7 Close up showing raised ink on paper surface from a recessed printing process viewed under oblique lighting (x25 approx.).

Figure 5.8 Microprinting (x25 approx.).

Chapter 6: Materials Used to Create Documents

Figure 6.1 Multi-coloured thread for stitching (x25 approx.).

Figure 6.2 Perforated pages of a passport (x3 approx.).

Figure 6.3 Worked example: Note item 1.

Figure 6.4 Worked example: Crumpled piece of paper item 2.

Figure 6.5 Worked example: Torn edges from items 1 and 2 in close proximity.

Figure 6.6 Worked example: Paper sheared.

Figure 6.7 Worked example: Sheared edges overlapped to show correct physical fit.

Chapter 7: Analytical Techniques Used in Document Examination

Figure 7.1 A typical thin line chromatography plate showing the separation of ink components. Each component has its own separation factor, known as R

which is calculated by dividing the distance the component has migrated (X) by the distance travelled by the solvent (Y).

Chapter 8: Altered and Tampered Documents

Figure 8.1 The electromagnetic spectrum.

Figure 8.2 Two pieces of paper with similar crease patterns viewed under oblique light.

Figure 8.3 Shadow staple holes (x3 approx.).

Figure 8.4 Oblique light view of an abraded document close up (x3 approx.).

Figure 8.5 a and b. An obliterated entry before and after use of appropriate filters to reveal the original entry.

Figure 8.6 An entry covered with correction fluid viewed from behind the document illuminated with transmitted light.

Figure 8.7 Showing a close up of a shadow line suggesting a composite document.

Figure 8.8 Worked example: Agreement, item 1.

Figure 8.9 Worked example: Handwriting specimen.

Chapter 9: Indented Impressions

Figure 9.1 The dark grey line is typical of that produced by an impression and the pale tramlined line (running from bottom left to top right) is typical of that produced by an inkline on the paper. Where they cross (arrowed) any break in the lines may indicate whether the impressions were present on the page before the ink or vice versa (×3 approx.)

Figure 9.2 Worked example: Electrostatic trace from the hold up note.

Figure 9.3 Indented impressions revealed using an oblique light source to produce shadows created by the deep impression.

List of Tables

Chapter 5: The Examination of Printed Documents

Table 5.1 Diagnostic features of printing processes

Essentials of Forensic Science

Titles in the series:

An Introduction to Forensic Genetics,

Second Edition

William Goodwin, Adrian Linacre and Sibte Hadi

Forensic Botany: A Practical Guide

David Hall and Jason Byrd

Wildlife DNA Analysis: Applications in Forensic Science

Adrian Linacre and Shanan Tobe

Forensic Approaches to Buried Remains

John Hunter, Barrie Simpson and Caroline Sturdy Colls

The Forensic Examination and Interpretation of Tool Marks

David Baldwin, John Birkett, Owen Facey and Gilleon Rabey

Foundations of Forensic Document Analysis

Theory and Practice

Michael Allen

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Library of Congress Cataloging-in-Publication Data

Allen, Michael (Michael John), 1959- , author.

Foundations of forensic document analysis : theory and practice / Michael Allen.

p. ; cm. {\emdash} (Essentials of forensic science)

Includes bibliographical references and index.

ISBN 978-1-118-64689-2 (cloth)……ISBN 978-1-118-72993-9 (paper)

I. Title. II. Series: Essentials of forensic science (Forensic Science Society)

[DNLM: 1. Documentation. 2. Forensic Sciences{\emdash}methods. 3. Records as Topic. W 750]

RA1147.5

614′.1—dc23

2015006398

A catalogue record for this book is available from the British Library.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

About the Author

Mike graduated from Keble College, Oxford University in 1981 with a degree in Physiological Sciences and went on to obtain an MSc in Forensic Science from the University of Strathclyde. In 2011 he completed his PhD with the University of Staffordshire having researched handwriting development in children.

Mike's forensic career began in 1983 in the Questioned Documents section of the Forensic Science Service laboratory in Birmingham, UK. In 1992, together with six colleagues, he helped to set up Document Evidence Limited to supply forensic document examination in the private sector to many police forces, other public bodies as well as lawyers and private clients. In 2008 Mike decided to semi-retire leaving Document Evidence but continuing to do some casework until finally retiring from that in 2013 having examined thousands of cases and given evidence in court on hundreds of occasions. He has been teaching document examination in several universities for a number of years and continues to do so.

Mike was Lead Assessor in Questioned Documents in the Council for the Registration of Forensic Practitioners from its inception and continued to play a role until its eventual closure in 2009. He has also been manager for the diplomas in Questioned Documents and Identity Documents for the Chartered Society of Forensic Sciences (previously the Forensic Science Society).

Series Foreword

Essentials of Forensic Science

The world of forensic science is changing at a very fast pace in terms of the provision of forensic science services, the development of technologies and knowledge and the interpretation of analytical and other data as it is applied within forensic practice. Practising forensic scientists are constantly striving to deliver the very best for the judicial process and as such need a reliable and robust knowledge base within their diverse disciplines. It is hoped that this book series will provide a resource by which such knowledge can be underpinned for both students and practitioners of forensic science alike.

It is the objective of this book series to provide a valuable resource for forensic science practitioners, educators and others in that regard.

Professor Niamh Nic Daéid, FRSEUniversity of DundeeSeries Editor

Preface

What is document examination?

Forensic document examination is a wide ranging speciality that encompasses the examination of all aspects of document production. (The one examination type not involved is the examination of fingerprints on documents.) There are many aspects to document production, including handwriting and signatures, the examination of machine printed documents, alterations to documents, recovering information about how and when a document was produced, together with many other less frequently encountered problems—such as determining the sequence in which intersecting ink lines were written. The knowledge and experience required by the document examiner for handwriting comparisons thus ranges from matters such as the kinds of features to be found in handwriting, the determination of line fluency or the effects of age on handwriting, to an understanding of the components of ink and how they may be compared optically and chemically, to the composition of paper (potentially to the extent of determining how to identify tree species that make up a sheet of paper), to a knowledge of how mechanical devices such as typewriters, computer printers and printing machines work.

In other words, for a practitioner to be able to examine a document as a whole, rather than just some particular aspects of it, a broad, scientific training is invaluable.

In some countries the different subsets of the document examiner's scope are indeed divided up, for example there might be a handwriting expert, a forensic chemist to examine inks, an electron microscopist to look at the components in paper and a botanist to look at the tree species present. Traditionally, in the UK, many forensic document examiners deal with most of these sub-specialities. This has the advantage that a document can be considered from a number of angles by the same individual scientist who may then be best placed to integrate the information from different examination types to reach a more meaningful overall conclusion. For example, if a questioned agreement consisting of several pages is examined and contains typed entries, a signature and some handwritten annotations, then the document examiner has several lines of enquiry to follow whereas often the focus by non-experts would only be on the authenticity of the signature. A practitioner who only examined handwriting would therefore not necessarily be in a position to consider other lines of enquiry, such as page substitution or addition of entries at a later time.

Purpose of this book

The teaching of forensic science in universities in the UK has undergone significant change over the last 20 years, going from a subject taught at postgraduate level in a couple of universities (particularly those at the University of Strathclyde and Kings College, London), to undergraduate courses in many universities. This explosion of undergraduate courses has coincided with a number of excellent textbooks being published that cover all aspects of forensic science.

The content of general forensic science courses is inevitably divided up into various disciplines covering the mainstream topics such as biological material and physical evidence. Disciplines such as document examination therefore tend to form a small part of a much wider syllabus, and it is inevitable that the vast majority of students will not be seeking to pursue document examination as a career.

The teaching of some areas of forensic science has been made more difficult because the experience of the practitioner is such a valuable and essential part of the learning experience that it is not easy to impart knowledge to students other than in a detached 'textbook' fashion. And many that teach forensic science recognise the value that teaching by practitioners brings to the students' appreciation not just of the academic content but also the practical and court-related experiences that go with it.

So why write a textbook for students on this small part of their syllabus? While the majority of students will not become document examiners, the general forensic science student textbooks can only give a fairly brief (typically one chapter) outline of the subject. This book aims to extend that coverage primarily for students who want more than they can get from a general forensic textbook but less than they would get from one of the excellent books aimed more towards professional (especially training) document examiners.

Students inevitably have a different perspective on forensic science than that of practitioners, particularly as students need to acquire academic knowledge perhaps more than practical experience, although of course the two are closely entwined. So as a textbook aimed at students, the content of this book is different in some respects from that to be found in the practitioner texts. In addition, there is a need to not presume that readers have all of the basic knowledge needed to follow the diverse topics covered in the text. This in part is a reflection of the different subject backgrounds from which students come (which is translated into diverse degree subjects amongst practising document examiners). For these reasons, there are information boxes scattered throughout the chapters that contain what is intended to be helpful additional information for those not so familiar with some aspects of the subject.

Document examination is a very visual subject and it is inevitable that many explanations are enhanced by the use of images. In addition, it is probably the case that a good image reinforces the retention of the information in the text. For these reasons, there are plenty of diagrams and photographs to help make the words more readily understood.

Like all areas of forensic science, document examination produces a steady stream of published papers in scientific journals and forms the subject of conferences throughout the world. These rich sources of material are an important part of the subject at both academic and practitioner levels. For students, they provide an opportunity to enhance their academic understanding of the subject by digging deeper and deeper into the science behind the topics within the specialty. There are, therefore, plenty of references in the text to further reading for those minded to follow up aspects that they find particularly interesting.

In recognition of the continuing research developments and to enhance the content of the book there will be online updates detailing interesting new research papers and further worked examples to refresh the material available. To that extent, the book will always be a 'work in progress' in keeping with the steady accumulation of knowledge and technological changes over time. There are a number of topics currently that are of particular interest, including the attempts to harness the power of computers to assist the handwriting expert in a variety of contexts including automatic signature recognition (and the potential role of signatures as a biometric to identify a person) and giving some objective measures of handwriting features, the many different technologies applied to ink comparisons and a variety of conceptual approaches to dating ink on documents.

Structure of this book

The sub-topics that make up forensic document examination are in many ways fairly conceptually separate and this makes dividing the book up into self-contained chapters easier. However, there are elements that cross examination types and these relate especially to the procedures used when carrying out practical casework.

While this book is not intended to focus too heavily on those aspects that are better covered in books aimed at practitioners, it is essential that students are given a taste of what happens in the real world of casework. In order to achieve this each chapter finishes with two sections that first describe the kinds of information that are expected to be recorded by a practitioner working a case (note taking) and second some thoughts about how cases should be reported. While it was tempting to put the note taking into a separate chapter, as the principles that are involved are similar whatever the examination type being carried out, each different topic does require the recording of different sorts of information and hence each chapter will contain suggestions of what needs to be noted and why for the relevant topic.

At the end of most chapters there are worked examples that show how some mocked up cases could be examined in terms of notes taken and how they might be reported. The worked examples are intended to help fill the gap between reading and doing that will be familiar to many students. It is worth saying here that there are no universally agreed methods by which note taking should be done or examinations carried out. Nonetheless, the methods described in this book work and have stood the test of time for many practitioners.

As mentioned above, there are some books already available that cover forensic document examination or particular aspects of it and some of these are listed below. This book, therefore, aims to fill the gap between a chapter in a general forensic textbook and the more specialist books listed in the Further Reading section.

The author will be adding new references that are relevant as they are published and some more worked examples from time to time. Please visit qdbook.blogspot.co.uk for more details.

Acknowledgements

I have always been concerned over whether there was a gap in the market of excellent books that cover forensic document examination. However, I was convinced that for students, in particular, there was a need for a book showing how the practical side of the speciality was grounded in a robust theoretical framework. The journey from theory to practice is, in my experience, not always an easy one for students to make as they don't have the daily immersion in a subject that a trainee forensic document examiner would have, for example.

I therefore have been very fortunate to have the views of a recent student and now fully qualified document examiner responding to my question: Would this book have been helpful to you as a student? I am extremely grateful to Hannah Pocock for her enthusiastic help in making sure that this book keeps its focus on its intended audience and will, I hope, be beneficial to their studies. In addition, I am very grateful to Dr Andy Platt at Staffordshire University for looking over and suggesting some amendments particularly to Chapter 7. But, of course, I take full responsibility for the content of the book, not as daunting as taking responsibility for giving evidence in court as an expert witness, but daunting nonetheless knowing that attaining perfection and pleasing all readers is impossible!

I am very grateful to those at Wiley Blackwell who have helped me along the way in the, to me, new venture of book writing, in particular Rachael Ballard, Fiona Seymour, Audrie Tan, Delia Sandford and Rachel Roberts.

It goes without saying, but I will say it anyway, that without the cooperation of my family and especially my wife Karen, finding the time to write the book would have been that much more difficult.

About the Companion Website

Foundations of Forensic Document Analysis: Theory and Practice is accompanied by a companion website:

www.wiley.com/go/allen/forensicanalysis

The website includes:

Powerpoints of all figures from the book for downloading

Chapter 1Introduction

Forensic document examination, like all forensic specialties, is first and foremost based on knowledge. However, there are many other important aspects to the job that should not be overlooked because knowledge on its own is not enough to ensure the competence of experts. In this chapter these other aspects are described to give the reader some idea about these issues, which are easily overlooked but which are vital if the quality of forensic procedures is to be fit to be put before the courts.

1.1 Historical background

Just when and where writing started is not certain, but it has been around for thousands of years and probably first appeared in the eastern Mediterranean, at least partly driven by the need to record trading transactions among seafaring nations such as the Phoenicians – who may have been the first to create an alphabet.

Whatever its historical origins, once people started to write it was inevitable that others would start to abuse the written form for fraudulent reasons. In the intervening years, the criminal motivations have probably changed very little but the means to achieve them have changed beyond all recognition.

Document examination, and in particular handwriting examination, has been a recognised specialty in the context of the judicial systems of many countries for well over 100 years. Part of the reason for its early inclusion centres on the importance of handwriting, and in particular signatures, as a mark of agreement and endorsement to authorise various business and other transactions. The need for a third (independent) party to give an opinion about the genuineness, or otherwise, of disputed signatures and handwriting can readily be appreciated.

As technology developed in the late nineteenth and throughout the twentieth century new problems for document examiners arose in tandem with the expansion of business and commerce across the world, and as a result much of the work of the expert is concerned with commercial transactions. Nonetheless, the domestic environment continues to produce its share of cases, from anonymous letters to ransom demands to murder and terrorist activities.

Other strands of document production have their own separate histories, such as the production of paper, the use of printing, advances in ink formulation and writing implements and the development of the typewriter and its eventual replacement by the computer printer. The many faceted work that faces the document examiner tasked with determining a document's authenticity has made the specialty a mainstream forensic discipline present in forensic science laboratories across the world.

In the early days of the specialty, textbooks on document examination were few and far between and they generally focused on handwriting and signature examination, but in 1910 in the USA the first book to draw the disparate examination types together into one place was written by Albert S. Osborn and entitled Questioned Documents. Since then a number of textbooks have been written, each one able to give more up-to-date information as methods have improved and developed.

While document examination is widely regarded as a mainstream forensic specialty, and certainly there is no disputing the need for experts in this discipline if cases involving documentation are to be prosecuted, one question that needs answering is: Are the underpinning foundations of document examination robust? Or put another way, can the courts rely on the evidence that forensic document examination provides (and that individual practitioners present in a given case)?

1.2 Is document examination a science at all?

Forensic science, by its high profile nature and the considerable public interest in the subject – both in the real world and in fiction, is perhaps one of the most scrutinised of scientific endeavours. Given the consequences that arise from it (fines, imprisonment and more depending on the country) it is of course quite right that all areas of forensic science should be able to justify themselves so that the public can be as sure as is humanly possible that the evidence presented to the courts is the best available.

And there is the first (and most intractable) problem – forensic science is a human endeavour – it does not exist in a world where uncertainty and error are somehow suspended in striving for absolute perfection and reliability. The possibility of error should be the single biggest factor influencing practitioners as they endeavour to maintain as high a standard as possible in all that they do, as they determine the evidence in a case, and especially when assessing the weight of their evidence. Most of forensic science ultimately comes down to interpreting evidence, and that is a cerebral process conducted by the expert, whatever the specialty, based on whatever evidence has been discovered and evaluated. Thus, using technology to detect, analyse and measure amounts of material (be it drugs in the body or DNA on clothing) is often just the foundation upon which the expert's opinion is based. There are instances when the technology may effectively be providing the expert evidence – such as identifying what a suspicious white powder is (of course, using the technology correctly is itself an endeavour requiring expertise). But expert evidence is human opinion evidence, not machine-generated data. Indeed, one of the most important factors that defines expert witnesses is that they are allowed to, indeed are encouraged to, express an opinion about the significance of their findings. Opinion evidence is almost forbidden from other categories of witness in many legal jurisdictions.

In this context, the specialty of document examination will be seen in the following chapters to have to admit that it does not always have many databases upon which to call when assessing evidence. The greatest focus of criticism of the specialty has generally been on handwriting and signature examination (Risinger et al. 1989). As we will see in this book, much work has been done by various researchers to address some of the criticisms and in so doing provide reassurance that the knowledge and processes that underpin the specialty of document examination are of sufficient reliability to justify their use. The capability of individual practitioners is a separate matter that also needs consideration.

In many areas of science, the use of computing power has transformed the methods and procedures used and it is not surprising that this is also true in document examination, particularly so in handwriting and signature identification. Perhaps one of the principal motivations for such an approach is to remove (or reduce) the human element of the expert's opinion and replace it with a mathematical (non-human) result based upon a de-personalised evaluation of the evidence. In Chapter 2 some consideration is given to the use of computers in handwriting examinations. The fact is, however, that despite considerable amounts of research into computer-based methods of assessing handwriting, no method has emerged to replace the human expert. At best, some of the findings of these research endeavours provide assistance to, but in no way yet replace, the human expert.

The reason for this is that of all of the ‘things’ that forensic practitioners examine (from paint to glass to body fluids), handwriting is unusual in being the constantly varying physical product of the human mind and body, unlike any other physical material that forensic science tries to examine. (Some of the closest relations are forensic phonetics and forensic linguistics, which seek to examine the human voice and the way that we use language, respectively, and forensic gait analysis, which assesses how we move as we walk.) Handwriting examination does not have the luxury of having invariant materials to look at, be they glass fragments, flakes of paint, or stains from biological fluids, the analyses of which do not have to cope with intrinsic natural variability let alone variability that is under human control.

It can readily be seen why technological solutions that address questions such as ‘what is this thing made of’ are less difficult to answer than questions such as ‘who did this handwriting’, for example, given that every piece of handwriting is unique and people may deliberately try to disguise their writing or else someone may try and copy their handwriting. How does a computer [operator] factor in even those basic issues since there are no global rules that dictate how good or bad a particular person is at writing (or how variable it is), disguising or copying?

The study of handwriting can currently only be carried out by human practitioners, albeit potentially with some assistance from computers that can provide some supporting information in some instances. The processes involved in handwriting comparison are described in Chapter 2. In some ways the requirements are really quite simple to describe, as in essence they require a forensic document examiner to undertake a lot of study around the subject and gain experience in examining handwriting from many people in many case situations to build up a personal database of experience and information. This may seem to be a cause for concern since this leads to experts forming opinions based on reasons that are not freely available in the public domain but are rather based on thoughts that occur in their heads. This misses the point that experts must be able to show they have followed appropriate methods (such as those described in Chapter 2) and they must be able to demonstrate and justify their opinions to others (such as the court). Any specialty that allowed practitioners to say ‘This is my expert opinion, take it or leave it’ would rightly be discounted. Ironically, the more technologically advanced the methods used by a forensic practitioner, the more there is an element of trust between their evidence and those using it, simply because the complexity of the technology is beyond the understanding of the lay person. Indeed, the actual working of a piece of equipment may not be fully understood by the person operating it, but the results obtained from it (from which the evidence is then derived) are of course understood.

Science can be defined as an intellectual and practical activity requiring the comprehensive study of the structure and behaviour of the world by observation and experiment. Looking at the elements of this definition in relation to handwriting, the activity of handwriting examination encompasses both intellectual (interpreting what is observed) and practical (observing and recording findings) aspects. The examination process is comprehensive (it is based on a thorough and complete process not focusing on isolated aspects). The relevant structure is in the handwriting (and an understanding of its physiological origins) and the behaviour is covered by an understanding of the capabilities of people when writing. The experimental dimension is given in the body of published knowledge that can be drawn on by practitioners. And careful observation is the single most important element of the examination process whatever the forensic specialty.

The notion that science somehow exists outside of human endeavour, in particular in a machine-based, infallible and statistically perfect world, is not only wrong, it is potentially dangerous precisely because the human elements of understanding and interpretation can be all too readily subsumed to a machine that then conveniently becomes the source of error (thereby allowing a practitioner to be absolved from any implied criticism when an error occurs). This diminishes the role of the (human) expert to the point where personal responsibility for the evidence placed before, say, a court is deflected to machines.

Looking at this another way, there is an expectation that human forensic practitioners are infallible when presenting their evidence. This is as unreasonable as it is ridiculous. No aspect of human endeavour can live up to such a high level of pressure, not medical science, not computer science, not even the law.

The National Academy of Sciences report (National Research Council, 2009) into forensic science added another layer to this debate by insisting that any specialty should justify its methods and also require a process of ensuring that individual practitioners can demonstrate an appropriate level of competence. In other words, there is a (deceptively) simple two-stage process needed to make sure that the science is good and that the scientist is good, or more broadly, that the methods used in any forensic specialty are good and the practitioners are good (hence side-stepping the issue of just what constitutes science with all of the mental baggage that almost everyone attributes to it). Surprising to some might be the fact that even those specialties that are widely regarded as safest, from fingerprinting to DNA, are not immune from needing to demonstrate the theoretical and practical underpinnings of their practice.

Handwriting (with signatures) has come in for its share of attention in this wider debate and this has been very well summarised by Kirsten Jackson in Chapter 6 of the second edition of The Scientific Examination of Questioned Documents (Kelly & Lindblom, 2006). The standing of forensic evidence was tested in the US courts using what was often called the Frye test (named after a particular judgement in the USA) in which the concept of general acceptance of the methods and knowledge in a specialty amongst those working in the peer group was regarded as a reasonable approach to adopt. In other words, if most practitioners regarded a particular methodology acceptable then the courts would accept that as an adequate demonstration that it was sound.

In 1993, in the US Supreme Court, a decision was taken to consider this principle of general acceptance together with a different principle based on the idea that the court would accept evidence that was based on scientific or other specialised knowledge providing it was likely to assist rather than hinder the court and, crucially, it was left to the court to determine the acceptability (by questioning the experts) on a case-by-case basis. This was the so-called Daubert ruling.

These general principles then came to be applied to a case known in short-hand as Starzecpyzel in which the court described handwriting testimony as a technical skill rather than a science and called into question the underpinning of the subject. This has led to a number of studies (discussed in Chapter 2) to improve the published literature on the methods and reliability of handwriting and signature examinations in particular. Similar focus on improving the robustness of processes has occurred in other specialties. The net result has been a greater output of published materials aimed at demonstrating the underpinnings of all forensic specialties.

Specific cases and legal rulings do not apply to other countries and so these rulings did not have a direct influence in the UK. Nonetheless, forensic practice is a worldwide profession and it is wise that all practitioners should be mindful of developments elsewhere. There have been repercussions in the UK inasmuch as the legal authorities have looked at the standards behind expert evidence here too. In the UK a key role in this is played by the Forensic Science Regulator who is responsible for standards in forensic practice, working in conjunction with the practitioners in the various specialties.1

1.3 Quality assurance

The problematic nature of decision-making was highlighted in the previous section and its relevance to the forensic process is huge because forensic practitioners make many, many decisions during the course of their examinations. Depending on the specialty involved, the use of test results derived from various items of equipment will also need to be fed into the decision-making process. However, pieces of equipment, just like people, are also not infallible precisely because people build and maintain them.

Given these constraints, the notion of having another expert to check findings makes a lot of sense, since certain categories of error can readily be identified and corrected. Clerical errors are inevitably commonplace and having someone read over a report will reduce their occurrence – but not eliminate their possibility. To reduce the likelihood yet further, a second checker could be employed and even a third. This makes the point that all processes have to have a sensible limit, and having one or at most two checkers is a very fair and sensible way of reducing as close to zero as possible the probability of, say, clerical errors.

The request that an investigator makes of the forensic practitioner determines to a large extent what the expert will decide to do and, importantly, not to do in the case. It is to be expected that a busy expert may misread or misunderstand what is required and this highlights a second purpose of any checking procedure, namely to make sure that the relevant questions have been addressed in the expert's report. This may seem uncontroversial, but it can cause problems if during a forensic examination evidence is uncovered that has not been asked for by the investigator but which may be relevant to the overall matter in hand. The expert can either ignore the non-requested evidence (but that might lead to a miscarriage of justice) or notify the investigator or, better still, put it into the report even if the investigator (or some other interested party) seeks to have it removed and, more likely still, refuses to pay for the extra time spent on the additional examination.

The primary reason for checking an expert's findings, however, is to get a second expert's view as to whether the conclusion (and the reasons leading to it) is reasonable and the weight of evidence expressed (opinion) is consistent with the outcome of the forensic examination given the circumstances of the case. The views of a second expert are clearly valuable since if two experts agree then it is more likely that the conclusion is robust.

However, there is one difficulty, and that relates to how experts in any specialty acquire their knowledge and experience. We all learn the vast majority of what we know and can do from others who have gone before. In a forensic practice context, that means gaining knowledge at, say, university and then being trained in a particular laboratory environment to gain experience of applying our knowledge. This can tend to produce a situation where a practitioner does what they have been taught and, in due course, passes that on to the next generation. If several organisations are able to carry out forensic examinations in a given specialty, it is likely that they all operate in slightly different ways, due to slight variance in practice advocated by the individual experts in each place, but also constrained by, for example, the availability of equipment. There is, therefore, the potential for institutional differences of approach in a given specialty, and indeed this does occur (‘our lab does it differently to your lab’). In order to try to reduce the effect this might have on the consistency of evidence from different organisations, collaborative studies can be carried out that provide the same material for examination to those participating and the results obtained can then be compared and discussed. From such exercises, it is hoped that best practice (or good practice or, at least, highlighting bad practice) will emerge with a consensus view as to what methodologies are appropriate to given examination types.

Of course, practitioners can be tested to see how well they deal with such exercises. Testing is a normal part of most practitioners' work load. Tests can be declared (so that the practitioner knows it is a test) or undeclared (so-called blind trials). Declared trials tend to be much easier to arrange but they have the drawback that awareness of being tested does alter the ‘psychology’ of the situation with practitioners becoming more wary and looking for traps in the evidence, for example. Undeclared trials are better from this perspective since the practitioner treats them in a ‘normal’ manner, unaware that they are a test; but getting material into a laboratory with all of the administrative ‘red tape’ that is involved makes this a much less frequently used test procedure.

One particularly valuable form of testing is where experts in different laboratories are given the same test material and after completion the results are compared. This inter-laboratory regime is good at passing on good practice and should lead to common standards being applied so that the final users (investigators and the courts) obtain a reasonably uniform quality of result irrespective of which organisation they go to for their forensic services.

1.4 Standards in forensic document examination

There is much merit in the idea of determining and then publishing good practice guidelines in a forensic specialty for reasons of quality and consistency of evidence put before the courts. The highest level for such standards are the ISO standards published by the International Organisation for Standardisation (whose acronym varies in different languages so ISO was settled on as being similar to, but not identical with, any of the languages concerned). There is no ISO standard specifically for forensic practice, let alone document examination. The nearest standards that have been adopted are:

ISO/IEC 17025 General requirements for the competence of testing and calibration laboratories, and

ISO/IEC 17020 Conformity assessment – Requirements for the operation of various types of bodies performing inspection.

ISO 17025 is the standard that closest matches the function of forensic practice, especially laboratory-based examinations. ISO 17020 applies more to the crime scene and its inspection since there is less emphasis on analysis and interpretation at that point in an investigation. Having stressed the value of consistency and cooperation between organisations (not just those concerned with forensic practice) in the previous section, such cooperation has been formalised in the International Laboratory Accreditation Cooperation (ILAC), which publishes guidelines that help to achieve this, one of which, known as G19,2 has the purpose of interpreting the ISO 17025 standard in a forensic laboratory context.

The process of conducting assessments of laboratories against these two ISO standards is managed in the UK by the United Kingdom Accreditation Service (UKAS). The assessment process is very detailed and looks at both the management of an organisation and at the technical aspects carried out by the practitioners within the organisation. The reasoning is essentially that both aspects must be fit for their intended purpose if an organisation is to function properly: in other words neither a well-run laboratory producing poor results, nor a technically competent but poorly organised laboratory, would comply with the standard. Much of the assessment process looks at records (paper-based or more often computer-based) of laboratory functioning covering typical business functions but with some emphasis on those that might impact on the technical side, for example the repair and maintenance records of equipment or the environmental control records in a DNA lab. The technical aspects involve the pieces of equipment used, the reliability of the results obtained from them and the interpretation made by the forensic practitioners. In parallel to this is an assessment of the staff capability and training needs and thus there is some focus on individual practitioners – not with a view to registering each individual as competent but to establish that the organisation properly supports staff and tests their competence appropriately (for example by using trial cases with known outcomes) so that only those practitioners that the organisation is satisfied are capable of dealing with particular cases will be allowed to do so.

Thus the ISO standards are generic and do not contain any information relating to specific specialties. ISO 17025 in particular is primarily focused on test results from a laboratory (with the emphasis very much on equipment-derived results) and has very little to say about the interpretation of findings that lead to expert opinion evidence. To fill the gap in specialty-specific standards, there are published guidelines in many areas of forensic practice that describe in general terms how to approach various types of examination. For example, there is SWG (Scientific Working Groups) DRUG for drug analysis and SWGDOC for document examination. The recommendations made by these Scientific Working Groups are available online3 and provide step-by-step summaries of good practice derived from the combined experience of a number of practitioners.

Another similar set of standards covering many aspects of scientific work, including a number relating specifically to document examination, is published by ASTM International (previously known as the American Society for Testing and Materials), which again can be obtained online.4

Compliance with the recommendations in these various standards is a good starting point for practitioners, who can be reassured that the practical methods that they employ are in keeping with what others in the field regard as appropriate.

Crucially, however, compliance with a standard or recommended approach is not a guarantee that the results obtained in a particular case will be correct or interpreted correctly. Obviously, the implementation of the methods and the interpretation of the findings require human skills, and this is where the competence of individual practitioners becomes the central issue.

1.5 Competence of forensic practitioners

The courts in most countries are the final arbiters of who can and cannot give expert testimony. In most countries, the courts have received advice as to how they should go about this because forensic evidence is widely recognised as being particularly valuable in many cases in assisting the court in its deliberations. Three of the key concerns are: (i) the robustness of the knowledge underpinning the specialty, (ii) the competence of the individual practitioner in front of the court and (iii) the relevance of the evidence to the case. Point (iii) is very much outside the practitioner's remit, but demonstrating individual competence is something that is central to establishing a witness's credibility.

In many professions, ranging from doctors to lawyers to architects, there are schemes that are designed to allow individuals to obtain recognition of their ability to do their respective jobs. Typically, such schemes may involve some sort of testing. Attitudes to such testing and the need for it have changed significantly in recent years, not least in the aftermath of the trial of Dr Harold Shipman for the murder of some of his patients, which had the consequence that professionals could no longer guarantee the trust of the public simply by virtue of their professional standing in the community. In addition, a number of high profile court cases in which forensic evidence played a significant part highlighted the need for forensic practitioners to justify their important place in the legal system.