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Statement Validity Assessment. Vrij: Chapter 8. What is Statement Validity Assesment?. A “verbal veracity assessment tool” Originated in Sweden (1963) as a method to determine the credibility of child witnesses in sexual abuse cases

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Statement Validity Assessment


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    1. Statement Validity Assessment Vrij: Chapter 8

    2. What is Statement Validity Assesment? • A “verbal veracity assessment tool” • Originated in Sweden (1963) as a method to determine the credibility of child witnesses in sexual abuse cases • Credibility of children in sexual abuse cases is critical, especially when there are no corroborating witnesses or physical evidence

    3. So… • Unlike non-verbal deception detection techniques, you are not looking for “tells” as to when a person is lying

    4. Problems with child witness testimonies • Vrij cites Craig, 1995, stating estimates range between 6% to 60% that child witness statements about sexual abuse are inaccurate • Due to parental influence, outside pressure, simple misidentification, or complete lies • Adults tend to mistrust statements made by children

    5. History of SVA • Udo Undeutsch and the West German Supreme Court • Presented case of a 14-year-old alleged victim of rape using a method called statement analysis • Court ruled that outside psychologists had more and better resources to determine truthfulness than court “fact finders” • 1955 – court requires use of psychological interviews and credibility assessments in disputed cases

    6. History of SVA continued… • Undeutsch was the first to create a comprehensive list of criteria to assess credibility • In 1988, Kӧhnken and Steller refined the criteria and standardized it in to a formal assessment procedure • Called it Statement Validity Analysis (SVA)

    7. History of SVA continued… • So… • The current SVA method wasn’t created until the 1980s, more than 30 years after the German courts looked in to statement analysis • Until this point, no studies had been done analyzing the validity of SA or SVA

    8. Four Stages of SVA • 1. Case-file analysis • 2. Semi-structured interview • 3. Criteria-Based Content Analysis (CBCA) • 4. Evaluation of CBCA with the Validity Checklist

    9. Stage 1: Case-File Analysis • Analysis of facts in a case • Expert forms hypotheses about what happened. Details from the analysis will help the expert focus on critical details later in the interview.

    10. Stage 2: Semi-Structured Interview • What the Criteria-Based Content Analysis (Stage 3) will analyze • Child gives his/her account of the allegation • Can be very difficult do to lack of verbal or cognitive skills in young children • Also highly influenced by personality factors such as anxiety or simple embarrassment • Skill and knowledge of interviewer is critical

    11. Stage 2: Semi-Structured Interview continued… • Interviewer must have a strategy for eliciting as much detailed information as possible • Has to ask the right questions in the right way • Must avoid leading, yes or no, questions • Must get child (or adult for that matter) to tell story without interviewer influence

    12. Stage 2: Semi-Structured Interview, continued… • Proper kinds of questions/techniques: • Open-ended (e.g. “Tell me what happened.”) • Facilitative responses • “OK”, “mmhm”, head nods, etc • Focused questions • Focus on specific details or aspects of the event • Problematic questions: • Leading (e.g. “Was it your dad?” • Option-posing (e.g. “Was the man white or black?”)

    13. Stage 3: Criteria-Based Content Analysis (CBCA) • Used on transcripts of the interviews • Consists of 19 criteria judged on a three point scale. • “0” if criteria is absent, “1” if criteria is present, “2” if criteria is strongly present • Consists of four categories

    14. Stage 3: CBCA – The Four Categories • 1. General Characteristics • 2. Specific Contents • 3. Motivation-Related Contents • 4. Offence-Specific Elements

    15. Stage 3: CBCA – General Characteristics (1-3) • 1. Logical Structure • Statement is coherent and logically consistent • 2. Unstructured Production • Information is presented in non-chronological order • 3. Quality of Details • Statement is rich in details

    16. Stage 3: CBCA – Specific Contents (4-13) • 4. Contextual Embedding • Events are placed in time and location • 5. Descriptions of Interactions • Statements contain information that interlinks the alleged perpetrator and witness • 6. Reproduction of Conversation • Specific dialogue, not summaries of what people said • 7. Unexpected Complications During the Incident

    17. Stage 3: CBCA – Specific Contents (4-13) Continued… • 8. Unusual Details • Tattoos, stutters, individual quirks • 9. Superfluous Details • Details that are non-essential to the allegation • 10. Accurately Reported Details Misunderstood • Mentioning of details outside a person’s scope of understanding • 11. Related External Associations

    18. Stage 3: CBCA – Specific Contents (4-13) Continued… • 12. Accounts of Subjective Mental State • Description of a change in a subject’s feelings during the incident • 13. Attribution of Perpetrator’s Mental State • Witness describes perpetrator’s feelings

    19. Stage 3: CBCA – Motivated-Related Contents (14-18) • 14. Spontaneous Corrections • 15. Admitting Lack of Memory • 16. Raising Doubts About One’s Own Testimony • 17. Self-Deprecation • 18. Pardoning the Perpetrator

    20. Stage 3: CBCA – Details Characteristic of the Offence (19) • 19. Offence-Specific Elements • Descriptions of elements that are known by professionals to be typical of a crime

    21. Stage 4: Evaluation of CBCA with the Validity Checklist • The CBCA score alone is not enough to determine if a person is being truthful • The examiner must also take into account other factors that could have affected the outcome • Leading by the interviewer, outside influences, witness’s cognitive abilities, etc… • The CBCA is NOT a standardized test

    22. Stage 4: Evaluation of CBCA with the Validity Checklist, continued… • Attempts to standardize the CBCA results through an 11 point checklist • Allows the examiner to consider alternative reasons for CBCA outcomes • As these alternative reasons are rejected, the CBCA results become stronger (in the assumption that the score represents the veracity of the statement)

    23. Stage 4: Evaluation of CBCA with the Validity Checklist, continued… • The Four Stages: • 1. Psychological Characteristics • 2. Interview Characteristics • 3. Motivation • 4. Investigative Questions

    24. Stage 4: Evaluation of CBCA with the Validity Checklist – Psych Characteristics • 1. Inappropriateness of Language and Knowledge • 2. Inappropriateness of Affect • 3. Susceptibility to Suggestion

    25. Stage 4: Evaluation of CBCA with the Validity Checklist – Interview Characteristics • 4. Suggestive, Leading, or Coercive Interviewing • 5. Overall Inadequacy of the Interview

    26. Stage 4: Evaluation of CBCA with the Validity Checklist – Motivation • 6. Questionable Motives to Report • Both for witness and other parties involved • 7. Questionable Context of the Original Disclosure or Report • 8. Pressures to Report Falsely

    27. Stage 4: Evaluation of CBCA with the Validity Checklist – Investigative Questions • 9. Inconsistency with the Laws of Nature • 10. Inconsistency with Other Statements • 11. Inconsistency with Other Evidence

    28. SVA – Issues • Effectiveness of individual criteria in CBCA • Effectiveness of Validity Checklist • Differences between laboratory and field studies • Detection rates and false-positives • Countermeasures • Applicability to adults? • The Daubert Standard

    29. CBCA – Issues • Not all statements are equally effective • A claim by a young child with less detail will be scored lower on the CBCA scale than that of an older child or adult • Not all criteria are created equal • Generally, the criteria in groups 1 and 2 are the most effective at distinguishing truth-tellers from liars

    30. CBCA – Inter-Rater Reliability • Are CBCA scores found by one rater close to those of a second, independent rater? • Good for most criteria, except unstructured production and spontaneous corrections • Overall score agreement is higher than on individual criteria

    31. Vrij’s Literature Review • Laboratory vs. Field studies • Deficiencies for one type are the other’s strengths • Lab – Not realistic, often based off observation of a video • Field – “Ground truth” cannot always be established, methods of finding it are not always consistent • In field studies, low quality statements are less likely to obtain a truthful diagnosis or a conviction/confession, even if true • High CBCA scores on false claims can lead to false-confessions or convictions • Therefore, relationship between CBCA scores and convictions or confessions may not be accurate

    32. Esplin et al., (1988) • Field study • CBCA scored on 0-2 scale (range of scores could be 0-38) • Confirmed statement average = 24.8 • Doubtful statement average = 3.6 • Differences between groups found in 16/19 criteria • However, there are criticisms…

    33. CBCA results from other studies • Boychuck (1991) – 13/19 • Lamb et al. (1997b)* – 5/14 • Plausible average = 6.74 • Implausible average = 4.85 • Parker & Brown (2000) – 6/18 • Rassin & van der Sleen (2005) – 2/5 • Craig et al. (1999)* • Confirmed average = 7.2 • Doubtful average = 5.7 • * used a 0-1 pt scale on CBCA

    34. Critical Difference to Non-verbal Studies: • All results found were in the expected direction, supporting the Undeutsch Hypothesis • Results in non-verbal studies are highly erratic • You may find non-verbal cues within individuals, but between groups these do not exist

    35. CBCA – Lab Studies • Difficult to create realistic situations • Accuracy rates ranged from 54% to 90% • Average rates for truths = 70.81% • Average rates for lies = 71.12% • Rates did not differ between children, adults, witnesses, victims, or suspects

    36. CBCA – Lab Studies, continued… • Serious methodological problems: • Different situations used • Different analysis methods used • Different amounts of training for raters • Some studies do not use the Validity Checklist and base diagnoses purely upon the CBCA

    37. CBCA – Lab Studies, continued… • But some important results remain • For the most part, all differences found were in the correct direction, once again supporting Undeutsch • Some individual criteria are more effective than others • Support percentages (differences found / studies investigated) • Range from 76% (Criteria 3) to 0% (Criteria 17)

    38. CBCA – Lab Studies, continued… • Other effective criteria: • 4. Contextual embeddings • 6. Reproductions of conversations • 8. Unusual details • Least effective: • 14-18 – Motivational Criteria • 17. Self deprecation actually occurred less in truth tellers in two studies

    39. CBCA – Classifications • 1. Discriminate (statistical) analysis is the most common method • 2. Rater makes own truth/lie classification • Computer analysis better at detecting lies • 80% vs. 60% for human raters • People better at detecting truths • 80% vs. 53% for computers • 3. General decision rules • E.G. Criteria 1-5, plus two others

    40. Reviewing the Validity Checklist • Focuses on three things: • 1. Age of interviewee • Highly affects cognitive abilities • Older age correlates with higher CBCA scores • 2. Interviewer’s style • Open-ended questions are most effective • The “Cognitive Interview” • 3. Coaching of interviewee • Countermeasures • Training of subject to include CBCA criteria in their statement • Easily defeat the CBCA analysis (only 27% of coached liars caught)

    41. What the lay-person believes… • Generally correct about number of details (Criterion 3) and descriptions of interactions (5) • Generally believe liars include more contextual embeddings (Criterion 4), unusual details (8), and superfluous details (9) in stories • Overall, the lay-person’s view differs somewhat from the experts’ view • This, potentially, is a good thing

    42. Problems with the Validity Checklist • Difficulty in identifying issues • Coaching by an adult is hard to discover • Difficulty in measuring issues • E.g. susceptibility to suggestion • Difficulty in determining impact of issues • The validity checklist is much more subjective and less formalized than the CBCA • It is therefore harder to study

    43. Vrij’s specific problems with VC • Issue 2 – Inappropriateness of Affect • Cites research that suggests there are two main psychological reactions to a rape • 1. Expressed style • 2. Numbed style • Issue 10 – Inconsistencies between statements • Human memory is not perfect, details can be unintentional • A practiced lie will not contain as many inconsistencies • Issue 9 and 11 (Consistency with laws of nature, consistency with other evidence) • Children’s scope of understanding often include fantasies and other things not in agreement with natural laws • Sometimes, even in a true allegation, no other evidence can be found

    44. Vrij’s specific problems with VC, continued… • Embedded false statements are difficult to detect • False memories

    45. The Daubert Standard • Daubert vs. Merrel Dow Pharmaceuticals, Inc. (1993) • Set standards for the inclusion of expert witness testimony in court cases in the United states • Consists of 5 criteria that must be met for evidence to be admissible in court

    46. The Daubert Standard, continued… • 1. Is the scientific hypothesis testable? • 2. Has the proposition been tested? • 3. Is there a known error rate? • 4. Has the hypothesis and/or technique been subjected to peer review and publication? • 5. Is the theory upon which the hypothesis and/or technique based generally accepted in the appropriate scientific community?

    47. So, what about SVA?

    48. Error rates • Refer to subjects that are classified incorrectly • Truth tellers classified as liars, and vice-versa • Error rate for CBCA judgments made in laboratory research is nearly 30% for both truths and lies • This is EXTREMELY high

    49. Overall evaluation of SVA • While results from research on SVA strongly support the Undeutsch Hypothesis, SVA does not meet the requirements of the five criteria established by the Daubert Standard • 70% correct classification is OK • 30% error rate is much too high for a valid test • Certain criteria in the CBCA appear to be highly effective at discriminating truth tellers from liars • Other criteria are wholly ineffective

    50. In the end… • CBCA and SVA would be an effective tool for use in the initial stages of investigations • Results from these tests can guide police throughout investigations • CBCA and SVA appears to be effective on adults also, not just useful in situations of child sexual abuse