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

Credibility of children in sexual abuse cases is critical, especially when there are no corroborating witnesses or physical evidence

So…

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

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

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

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)

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

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

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.

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

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

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?”)

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

Stage 3: CBCA – The Four Categories

1. General Characteristics

2. Specific Contents

3. Motivation-Related Contents

4. Offence-Specific Elements

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

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

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

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

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

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

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

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)

Stage 4: Evaluation of CBCA with the Validity Checklist, continued…

The Four Stages:– 1. Psychological Characteristics– 2. Interview Characteristics– 3. Motivation– 4. Investigative Questions

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

Stage 4: Evaluation of CBCA with the Validity Checklist – Interview Characteristics

4. Suggestive, Leading, or Coercive Interviewing

5. Overall Inadequacy of the Interview

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

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

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

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

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

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

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…

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

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

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

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

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)

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

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

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)

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

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

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

Vrij’s specific problems with VC, continued…

Embedded false statements are difficult to detect

False memories

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

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?

So, what about SVA?

CBCA Lab

CBCA Field

Validity Checklist

SVA

1. Is the scientific hypothesis testable?

Yes Problematic Problematic Problematic

2. Has the proposition been tested?

Yes No No No

3. Is there a known error rate?

Yes, too high No No No

4. Has the hypothesis been subjected to peer review/publication?

Yes Yes No No

5. Is the theory based on generally accepted principles?

Unknown Unknown Unknown Unknown

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

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

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