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Voicegram Identification Evidence

Gruber, J. S. and Poza, F.
1995: 54 Am Jur Trials, Lawyers Cooperative Publishing.



TABLE OF CONTENTS


I. PREFATORY COMMENTS
A. Introduction
。・1. In general
。・2. Purpose of article
。・3. Scope of article
B. Overview of Ongoing Controversy Over Voicegram Evidence.
。・4. In general
。・5. Causes of controversy
。・6. Basis of scientific criticisms
。・7. Examiner performance
。・8. Concluding observations
C. Terminology
。・9. In General
。・10. "Sound spectrogram," "Voiceprint," and "voicegram"
。・11. "Voice identification" and "speaker identification"
。・12. "Discrimination," "naming," and other voice "identification" tasks
。・13. "Reliability" versus "statistical reliability," and "validity" versus "statistical validity"
。・14. "False identification," "false positive," "False elimination" and "false negative"
II. SOUND, HUMAN SPEECH, AND VOICE IDENTIFICATION
A. Sound and Sound Waves
。・15. In general
。・16. Characteristics of sound waves
。・17. Frequency
。・18. Amplitude
。・19. Harmonic structure, resonances, and formants
B. Voice Characteristics Relating to Identification of Human Speech
。・20. In general
。・21. Uncertainty of specific voice features enabling effective voice identification
。・22. Uniqueness of voices-In general
。・23. Intra. and inter-speaker variability
。・24. Variability in forensic situations
。・25. Speaker situation
C. Types of Voice Identification
。・26. In general
。・27. Aural (non-voicegram) and audio-visual (voicegram based) voice identification
。・28. Innate, technical, and automated voice identification
。・29. Aural (non-voicegram) voice identification by layperson
。・30. Certain factors affecting ability to identify voices via solely aural method
。・31. Aural (non-voicegram) voice identification by experts
。・32. Voicegram voice identification by laypersons
。・33. Voicegram voice identification by experts
D. Apparatus and Production of Voicegrams
。・34. In general
。・35. Early analog apparatus
。・36. Digital audio spectrographic equipment
。・37. Miscellaneous uses of spectrographic sound analysis
III. HISTORY OF SOUND SPECTROGRAM VOICE IDENTIFICATION
A. In General
。・38. Introduction
。・39. Timetable
B. Early Period: Development and Initial Legal Application; 1941-1971
。・40. Origins of sound spectrography at Bell Labs
。・41. Spectrographic voice identification developed by Lawrence Kersta
。・42. Initial courtroom use
。・43. Initial dispute within scientific community
C. Middle Period: Tosi Study and Fairly Wide Acceptance; 1971-1979
。・44. Tosi study and results; Nash survey
。・45. Frequent courtroom testimony by Tosi and Nash
。・46. "Bolt II" and other scientific papers
。・47. Nash's errors and Tosi repudiation
。・48. Generally favorable legal decisions after Tosi study
D. Current Period: NAS Report and Mixed Legal Acceptance; 1979-Present
。・49. FBI sponsors NAS study
。・50. Butte County case
。・51. Current quiescent period
。・52. FBI survey
。・53. Daubert decision
IV. VOICEGRAM METHODOLOGY AND PROTOCOLS
A. Introduction
。・54. In general
。・55. Kersta protocol and methodology
。・56. FBI protocol
B. IAI Protocol and Methodology
。・57. In general
。・58. Preliminary examination
。・59. Spectrographic/aural analysis
。・60. Conclusions
C. Suggested Improvements to Protocols and Methodology

1. In General
。・61. Overview
。・62. Removal of bias
。・63. Method of obtaining speech samples
。・64. Suggested improvements to training procedures
2. Voice Lineups
。・65. In general
。・66. Criticisms of traditional "closed set" lineup
。・67. Sequential voice lineup
。・68. Illustrative spectrographic exemplars
3. Elimination Versus Identification Protocols
。・69. In general
。・70. Investigative variant
。・71. Suggested overall voice identification protocol
V. SCIENTIFIC ISSUES, CRITICISMS AND CONTROVERSIES
A. Introduction
1. Lack of Theoretical and Experimental Basis
。・72. In general
。・73. Inadequacy of existing research and studies
。・74. Lack of knowledge about relationship and relative probative value of aural and visual voice identification methods
。・75. Lack of knowledge about error rates and accuracy, especially in real-world, forensic situations
2. Factors limiting application of technique
。・76. In general
。・77. Checklist of factors
。・78. Voicegrarns of female voices
B. Tosi, et al., Extension of Experimental Results
1. Tosi "Extrapolation"
。・79. In general
。・80. Response to Tosi, et al., publication
。・81. Effect of feedback in experimental setting
2. Examination of Tosi's Assumptions
。・82. In general
。・83. Population of known voices; Pre-screening
。・84. Availability of time and responsibility of examiners
。・85. Decision options open to examiner, including "no opinion"
。・86. Availability of clues
。・87. Combined aural-visual versus solely visual comparisons

C. Tutorial on Subjective Decision making and Signal Detection Theory in Context of Voicegram Evidence
。・88. In general
。・89. Fundamental concepts of signal detection theory; Illustrative experimental protocol
。・90. Decision criterion
。・91. A priori probability
。・92. Values and costs
。・93. Real-world significance of examiner perception of a priori probability and of values and costs; Adapting experimental protocol to voicegram identification comparisons
。・94. Decision criterion
。・95. A priori probability
。・96. Values and costs
。・97. Receiver Operating Characteristic (ROC) curve
。・98. Likelihood of increasing false identifications as well as increasing false eliminations in true forensic situation
VI. ADMISSIBILITY AND OTHER LEGAL CONSIDERATIONS
A. Introduction
。・99. In general
。・100. Legal requirements for voice identification evidence
。・101. Uses of spectrographic-identification evidence
。・102. Communicating inherent limitations to finder of fact
B. Standards for Admissibility of Voicegram as Scientific Evidence
。・103. In general
。・104. Frye standard
。・105. Frye versus "McCormick" relevance standard
。・106. Daubert decision
C. Relevance, Materiality, and Competence
。・107. In general
。・108. Rule 403---Probative value versus prejudicial effects
。・109. Potential for misleading jury
D. Laying Foundation for Voicegram Evidence
。・110. In general
。・111. Components
E. Role of Trial Court
。・112. In general
。・113. Harmless error doctrine
F. Issues Related to Exemplars
。・114. In general
。・115. Obtaining exemplars
。・116. Access to relevant recordings
G. Opposing Voicegram Evidence
。・117. In general
。・118. Basis for challenging forensic experts
。・119. List of steps in opposition to voicegrarn evidence
H. Historical Trends
。・120. In general
。・121. Current admissibility status, by jurisdiction and significant decisions
VII. VOICEGRAM EXPERTS AND ASSOCIATIONS
A. Associations and Professional Requirements
。・122. In general
。・123. Past and current associations: IAVI and IAI
。・124. Educational requirements
。・125. Spectrographic training requirements
。・126. Certification
。・127. Ethics consideration
B. Retaining and Evaluating Examiners
。・128. In general
。・129. Evaluating examiner's credentials
。・130. Examiner's demeanor
。・131. Legal and courtroom experience and track record; Checklist
。・132. Fee structure
VIII. APPENDIX

。・133. Glossary

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