DAVID C. RASKIN, Ph.D., being first on his oath duly sworn, deposes and states :
1. I received my Ph.D. degree in psychology from the University of California, Los Angeles in 1963. I have served on the faculties of U.C.L.A., Michigan State University, University of British Columbia, and the University of Utah, where I presently hold the rank of Professor Emeritus of Psychology. For more than 38 years, I have conducted and published scientific research in human psychophysiology. For more than 27 years, I have conducted laboratory and field research on polygraph techniques for the detection of deception, taught university and applied courses about polygraph techniques, trained government and law enforcement polygraph examiners, and published extensively on polygraph techniques. I am also a licensed polygraph examiner in the states of Utah and New Mexico and have served as an expert witness in approximately 200 criminal and civil cases in federal and state courts in the United States and Canada. A copy of my Curriculum Vitae is attached, together with a copy of my chapter "Polygraph Techniques for the Detection of Deception" from my recent book entitled PSYCHOLOGICAL METHODS IN CRIMINAL INVESTIGATION AND EVIDENCE. This publication describes In more detail the Information presented below concerning such techniques.
2. Polygraph techniques for assessing the credibility of individuals are derived directly from basic scientific principles and research in psychology and human psychophysiology. The polygraph examination begins with a carefully structured interview (pretest interview) in which the issues to be tested are discussed in detail with the examinee. The specific questions to be asked during the test are then discussed in detail with the examinee. Three or four relevant questions concerning the issues under investigation are included in a series of approximately 9 to 12 questions that are answered simply "Yes" or "No" during the test, while recordings are made of the examinee's physiological responses to each of the questions. The entire set of questions is asked at least three times.
During the polygraph test, the polygraph instrument continuously measures and permanently records on polygraph charts the subject's physiological responses, which normally include respiratory activity, skin conductance (palmar sweating), relative blood pressure, and may also include blood flow in the finger (plethysmograph). After the test is completed, the polygraph charts are numerically evaluated by the examiner to determine if the pattern of physiological reactions indicates truthfulness or deception to the relevant questions. This is done by comparing the reactions to the relevant questions to the reactions produced when the examinee answered comparison or control questions (see 3. below).
3. Physiological measurement techniques for the detection of deception have been developed and subjected to scientific evaluation for almost 100 years, and the most commonly-used polygraph tests are based on generally accepted scientific principles. It Is well established that certain stimuli, such as questions to which a person is lying during a polygraph test, produce involuntary changes that are controlled by the autonomic nervous system. These reactions include increased skin conductance (palmar sweating), increased blood pressure, decreased respiratory activity, and decreased blood flow in the finger, all of which are measured with modern polygraphs.
Modern polygraph techniques grew out of law enforcement applications, and the most-commonly employed method is called the control-question test. In this technique, the questions include specific questions about the incident under investigation (relevant questions) and control questions that provide a meaningful way to compare and interpret the relative strength of the physiological reactions to the relevant questions The relevant questions directly address the issues under investigation, e.g., "Did you deliberately inflict the injuries that resulted in Matthew's death?" It is well established that deception to such a question would be highly likely to produce a substantial physiological reaction during the polygraph test.
Since the relevant questions are very important and potentially threatening to the examinee, many persons might react to the relevant questions even when answering truthfully. Therefore, control questions are used to provide an estimate of what the truthful (innocent) individual's reactions would be when answering a question deceptively. Such control questions may take one of two forms, probable lie questions and directed lie questions. Probable lie questions, e.g., "During the first 17 years of your life, did you ever do something dishonest or illegal?", are superficially related to the relevant issues, are deliberately vague, and are likely to be answered deceptively during the test. When directed lie questions are used, e.g., "During the first 17 years of your life, you ever violate even one rule or regulation?", the examinee is instructed to answer deceptively so that the examiner can see the pattern of reactions to a lie and then compare it to the relevant questions to see If the reactions are the same or different. This is a simpler and more straightforward procedure that is more accurate and is replacing the probable lie control questions.
With either type of control question, It is expected that the deceptive (guilty) subject will show stronger reactions to the relevant questions because of the concern about being discovered in deception on the Important issues of the test. However, the truthful (innocent) subject is expected to show stronger reactions to the control questions because of a concern that the reactions to the control questions do not clearly show an appropriate difference in reactions as compared to the relevant questions.
The interpretation of the test outcome is made by systematically comparing the strength of reactions to the relevant and control questions to determine if the reactions were consistently stronger to the relevant questions (indicative of deception) or stronger to the control questions (indicative of truthfulness to the relevant questions). This is known as numerical scoring, which involves assigning scores by comparing the relative strength of reactions to relevant and control questions. Negative scores are assigned when the reactions are stronger to relevant questions, and positive scores are assigned when the reactions are stronger to the control questions. This is done for the physiological measurement to each presentation of a relevant question, and the scores are totaled for the entire test. For all relevant questions combined, a total numerical score of 6 or lower indicates overall deception to the relevant questions, a total of +6 or higher indicates overall truthfulness to the relevant questions, and a total score less than 6 in either direction is inconclusive.
4. Considerable scientific research has demonstrated that the pattern of physiological changes during a polygraph test provides the basis for making highly accurate inferences concerning truth or deception when the examinee answered the relevant questions. The vast majority of the scientific evidence supports the reliability and validity of control-question polygraph tests for assessing credibility.
In 1987, a field study conducted with the cooperation of the Royal Canadian Mounted Police reported that R.C.M.P. polygraph examiners were 100% accurate on suspects who were later confirmed to be guilty and 90% accurate on suspects later confirmed to be innocent. In 1988, we completed a 3-year study at the University of Utah funded by the National institute of Justice, U.S. Department of Justice, using polygraph examinations conducted in criminal investigations by the U.S. Secret Service. The results showed an overall accuracy rate of approximately 95% both on suspects later confirmed to be guilty and those later confirmed to be innocent. In 1997, another field study using criminal cases from the R.C.M.P. indicated the examiners were 100% correct In detecting guilty suspects and 94% correct in identifying innocent suspects. It should be noted that research findings demonstrate that the confidence in test outcomes that indicate truthfulness is slightly higher than confidence in tests that indicate deception. Thus, a truthful polygraph test outcome is more likely to be correct than a test result that indicates deception. In other words, courts can be more confident in accepting a polygraph report that the accused person was truthful in her denials than a report indicating deception on the part of the accused.
5. The accuracy of polygraph examinations performed by me has been established in two published scientific studies. The first study entitled PSYCHOPATHY AND DETECTION OF DECEPTION IN A PRISON POPULATION by David C. Raskin and Robert D. Hare was published in 1978 in the scientific journal Psychophysiology, the journal of the Society for Psychophysiological Research. In that study, I examined 48 convicted felons, half of whom had been clinically diagnosed as psycopaths (sociopaths). My polygraph results were absolutely verified by scientific procedures and showed 100% accuracy of decisions on guilty subjects and 92% accuracy on innocent subjects. Not a single guilty subject, psychopath or non psychopath was able to beat the test. The second study entitled A FIELD STUDY OF THE VALIDITY OF THE DIRECTED LIE CONTROL QUESTION by Charles R. Honts and David C. Raskin was published in 1988 In the peer-reviewed journal Police Science and Administration, the official publication of the International Association of Chiefs of Police. In that Study, 25 examinations of criminal suspects were obtained from the case files of polygraph examinations conducted by Dr. Honts and Dr. Raskin. All polygraph results were verified by independent evidence of guilt and innocence, and independent evaluations of the polygraph charts from my examinations were performed by Dr. Honts. All of my results were verified and substantiated by Dr. Honts, and all of the polygraph decisions on my cases were shown to be 100% accurate on both verified guilty and verified innocent suspects. Copies of both of these scientific publications are attached.
6. In 1994, Professors Susan Amato and Charles R. Honts conducted a scientific survey of the U.S. membership of the prestigious Society for Psychophysiological Research, the International scientific organisation that represents the parent science for polygraph techniques. When asked their opinion of the usefulness of results obtained by means of properly-conducted polygraph tests, 83% of scientists who were well informed about the scientific polygraph literature indicated a favorable opinion of the diagnostic utility of polygraph results. These data are the most compelling evidence of the level of acceptance of the usefulness of the polygraph for assessing truth and deception.
7. On the basis of the scientific evidence and more than 27 years of academic, scientific, and professional experience with polygraph examinations and other forms of forensic evidence in criminal investigations, it is my scientific and professional opinion that properly conducted polygraph examinations have an accuracy rate that exceeds 90%. Furthermore, the confidence in a polygraph result indicating truthfulness is approximately 95%. Such examinations are widely employed and relied upon by almost all federal and local law enforcement and investigative agencies and those federal agencies concerned with national security. By comparison, many forms of forensic evidence that are commonly accepted in courts of law may have substantially lower rates of accuracy, as demonstrated by the LABORATORY PROFICIENCY TESTING RESEARCH PROGRAM funded by the National Institute of Law Enforcement and Criminal Justice, Law Enforcement Assistance Administration, U.S. Department of Justice and published in 1977. This study showed that many types of medical evidence, ballistics, blood, and hair tests had lower accuracy than the demonstrated 90% accuracy of polygraph examinations.
8. On 7 May 1997, I conducted a polygraph examination of LOUISE WOODWARD. The purpose of the examination was to assess her credibility with regard to allegations that she deliberately injured MATTHEW EAPPEN In performing the examination and the analysis of the results, I utilised all of the scientifically-validated procedures described above. I discussed the issues in great detail with WOODWARD during the pretest interview. I then reviewed all of the questions with her, which included the following relevant questions:
R1. ON FEBRUARY 4, 1997, DID YOU HIT OR STRIKE MATTHEW ON THE HEAD?
Answer: No
R2. ON FEBRUARY 4, 1997, DID YOU DELIBERATELY HIT MATTHEW'S HEAD AGAINST A HARD OBJECT OR SURFACE?
Answer: No
R3. OTHER THAN TRYING TO AROUSE HIM ON FEBRUARY 4, 1997, DID YOU INJURE MATTHEW BY FORCIBLY SHAKING HIM?
Answer: No
R4. DID YOU DELIBERATELY INFLICT THE INJURIES THAT RESULTED IN MATTHEW'S DEATH?
Answer: No
The sequence of questions, which included the above questions and directed lie control questions, was asked three times while physiological recordings were made on a state-of-the-art computerized polygraph system. I then numerically evaluated the results using the scientifically-validated numerical scoring procedure described above.
The results of the polygraph test of LOUISE WOODWARD indicated a total overall score of +12 and a pattern scores on the relevant questions that is indicative of the truthfulness of WOODWARD's statements as embodied in the relevant questions listed above. On the basis of the scientific evidence cited above, the confidence in the truthful outcome obtained by LOUISE WOODWARD is approximately 95%.
Copies of the polygraph charts, complete question list, and my report of the examination are attached.
I declare under penalty of perjury that the above is true and correct to the best of my knowledge.
David C. Raskin, Ph.D.
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