Introduction

This webpage provides information about:

• Morrison, G.S. (In Press). Forensic voice comparison. In I. Freckelton, & H. Selby (Eds.), Expert Evidence (Ch. 99). Sydney, Australia: Thomson Reuters.

Due to technical issues, publication has been delayed from the original July/August 2010 date.

Expert Evidence is a major subscription based service available in paper and online and is a unique and well respected publication offering comprehensive coverage of over 75 expert witness fields. Expert Evidence is essential for preparation and case presentation by litigation lawyers (both civil and criminal), forensic specialists, and any expert drawn into investigations or hearings. The editors of the service are Dr Ian Freckelton SC, a leading member of the Victorian Bar and Hugh Selby, Associate Professor in the Legal Workshop, Law Faculty, of the Australian National University. Contributing experts are drawn from accredited laboratories, respected consultancy firms and highly regarded individual academics and practitioners.

As part of the Expert Evidence series the 100-page Forensic Voice Comparison chapter is aimed first at lawyers, judges, police officers, and potential jury members; however, it is hoped that this chapter will also be of interest to forensic scientists, phoneticians / speech scientists, speech-processing engineers, and students of all these disciplines. It introduces forensic voice comparison in a relatively non-technical way, assuming a reader who has no prior knowledge of the subject. The focus is on the understanding of concepts and the provision of basic knowledge.

Comments

• “Morrison has a very nice writing style and I think he has phrased some of the fundamental matters in a way that is more clearly put than I have ever seen. I think he has done a masterly job.”
  • Dr John S. Buckleton, Principle Scientist, ESR Forensics, Auckland, New Zealand
    
    
• “It is very informative and at the same time easy to read – a rare combination. Its a great book.”
  • Dr Michael Jessen, Senior Scientist, Department of Speaker and Audio Analysis, Federal Criminal Police Office, Wiesbaden, Germany

Contents

• INTRODUCTION
  • What is forensic voice comparison?
  • Audience
  • Structure
  • Questions
    
    
• A PARADIGM SHIFT IN FORENSIC-COMPARISON SCIENCE
  • A paradigm shift
  • The new paradigm
  • Further reading
    
    
• THE LIKELIHOOD-RATIO FRAMEWORK FOR THE EVALUATION OF FORENSIC-COMPARISON EVIDENCE
  • Introduction
  • The likelihood-ratio framework
  • Why the forensic scientist must present the probability of evidence, and must not present the probability of hypotheses
  • Terminology
  • A database representative of the relevant population
  • Differences between DNA data and voice data
  • Calculating a forensic likelihood ratio
    • Calculating a forensic likelihood ratio from discrete data
    • From discrete data to continuous data
    • Calculating a forensic likelihood ratio for continuous data
    • Calibration and fusion
  • Further reading
    
    
• ASSESSING THE VALIDITY AND RELIABILITY (ACCURACY AND PRECISION) OF FORENSIC-COMPARISON SYSTEMS
  • Measuring the accuracy of a forensic-comparison system
  • Measuring the precision of a forensic-comparison system
  • Using measures of accuracy and precision
  • Tippett plots
    
    
• PROBLEMS AND OPPOSITION
  • Misinterpretations of forensic likelihood ratios
    • The prosecutor’s fallacy
    • The defence attorney’s fallacy
  • Opposition to the adoption of the new paradigm
    
    
• HUMAN VOICES
  • Introduction
  • Vocal tract
  • Vowels
    • Description
    • Forensic value
  • Nasals
    • Description
    • Forensic value
  • Fricatives
    • Description
    • Forensic value
  • Plosives
    • Description
    • Forensic value
  • Laryngeal activity
    • Description
    • Forensic value
  • Further reading
    
    
• VOICE RECORDING AND VOICE TRANSMISSION
  • Voice recording
  • Voice transmission
    
    
• APPROACHES TO FORENSIC VOICE COMPARISON
  • Introduction
  • Auditory approach
    • Description
    • Evaluation
  • Spectrographic approach
    • Description
    • Evaluation
  • Acoustic-phonetic approach
    • Description
    • Evaluation
  • Automatic approach
    • Description
    • Evaluation
      
      
• EXAMPLES
  • Introduction
  • Acoustic-phonetic example
    • Data
    • Acoustic analysis
    • Likelihood ratio calculation
    • Results
  • Automatic example
    • Data
    • Acoustic analysis
    • Likelihood ratio calculation
    • Results
      
      
• COMPARISON OF TECHNICAL FORENSIC VOICE COMPARISON AND NON-TECHNICAL SPEAKER IDENTIFICATION
  • Introduction
  • Non-technical speaker identification versus technical forensic voice comparison
    • Non-technical speaker identification
    • Technical forensic voice comparison
    • Mistaken beliefs about non-technical speaker identification
    • True earwitnesses versus listening to audio recordings
  • Validity of non-technical speaker identification
    • Variability between listeners
    • Listener certainty
    • Listener’s familiarity with speaker’s voice
    • Typicality of speaker’s voice
    • Duration, content, and quality of speech material
    • Prior expectations
  • Example
    • Variability between listeners
    • Listener certainty
    • Listener’s familiarity with speaker’s voice
    • Typicality of speaker’s voice
    • Duration, content, and quality of speech material
    • Prior expectations
    • Outcome
      
      
• APPENDIX A: INTERNATIONAL PHONETIC ALPHABET
  
  
• APPENDIX B: TRAINING AND ASSOCIATIONS
  • Training
  • Associations
    
    
    

About the Author

Dr Geoffrey Stewart Morrison is the Director of the Forensic Voice Comparison Laboratory, School of Electrical Engineering & Telecommunications, University of New South Wales. He is Principle Investigator on an Australian Research Council Linkage Project aimed at improving the validity and reliability of forensic voice comparison via the combination of acoustic-phonetic and automatic approaches and making forensic voice comparison of demonstrable validity and reliability a practical everyday reality in Australia (partner organisations include the Australian Federal Police, the National Institute of Forensic Science, and the Australasian Speech Science and Technology Association).

Dr Morrison is also an Invited Lecturer in the Judicial Phonetics Specialisation of the Master in Phonetics and Phonology Programme, Consejo Superior de Investigaciones Científicas (CSIC) [Spanish National Research Council] / Universidad Internacional Menéndez Pelayo.

Dr Morrison was awarded his PhD by the Department of Linguistics, University of Alberta in 2006. His doctoral and postdoctoral work (supported by fellowships from the Social Sciences and Research Council of Canada) focussed on statistical modelling of second-language speech perception. He began work on forensic voice comparison in 2007 when he was appointed Research Associate on an Australian Research Council Discovery Project conducted by Dr Philip Rose at the School of Language Studies, Australian National University.

More information about Dr Morrison’s research can be found at http://geoff-morrison.net and http://forensic-voice-comparison.net.

Purchase

Upon publication a pdf of the chapter can be purchased directly from the publisher.

Promotions

• In conjunction with Dr Morrison’s tutorial presentation at the Audio Engineering Society Conference on Audio Forensics, Hillerød, Denmark, 17–19 June 2010, an extract from the chapter was published in the conference proceedings.
  
  
• In conjunction with Dr Morrison’s tutorial presentation at the Pan-American/Iberian Meeting on Acoustics, Cancún, Mexico, 15–19 November 2010, the publisher will make downloads of the chapter available at half price.
  
  
  

Archive

The Morrison (2010) chapter replaces a 2003 chapter The technical comparison of forensic voice samples by Philip Rose.

Upon publication of Morrison (2010), the pdf of Rose (2003) will be made available here.

This webpage is maintained by the author, not the publisher.
Last update 22 August 2010.