Critique of The Expert’s Role in Forensic Assessment and as a Witness in Court

An expert witness is an individual with training, knowledge and experience that assists the judge or the jury to understand the evidence or the scientific, technical and specialized facts regarding the case. Additionally, experts are often questioned about their opinion which they developed based on their expertise and the facts about the case. It is also the role of the expert witness to teach and explain the basics to the solicitors and educate them about the issues that they are not personally familiar with. With their help, the defence can be built on scientifically accurate information. The testimony of experts has to be clear and logical, they have to speak slowly and clearly, be truthful and as accurate as possible. This essay will draw from psychological theories to critique the role of the expert in forensic assessment and as a witness in court. More specifically the theory of confirmation biases, social role theory and source credibility theory will be discussed in relation to expert witnesses and their testimonies.

Experts are required to have knowledge about a specific issue at hand and not only be familiar with the area in general. However, meta-analyses of past expert reports have shown that not all experts meet the standards for testifying. Faust and Ziskin (1988) and Giannelli and McMunigal (2007) discussed the controversial discussions about the role and benefits or damages the expert witnesses can cause. Researchers think experts need to be more transparent about the significance or insignificance of findings provided. Additionally Duquette (1981) emphasized the concern about overlooking or overcompensating experts’ expertise and experience.

One of the key findings of previous research was the fact that one fifth of expert witnesses who testified, were not qualified to provide a valid and reliable psychological opinion. Many expert witnesses lack the focus on reflecting unbiased, independent assessment.

There are however standards that experts have to meet in order to be considered as an expert witness. These standards were first presented by Daubert in late 20th century, serving as guidelines for the judge to decide whether expert's testimony is admissible or inadmissible and is overall beneficial or necessary for the testimony.

The criteria covers four categories, discussed in Rogers and Johansson-Love (2009) and Shapiro et al. The experts' opinion and their expertise have to be falsifiable, tested or proven to be false. There has to be an error rate regarding the facts they are providing. The facts have to be peer-reviewed/published and overall generally accepted.

The Committee on Ethical Guidelines for Forensic Psychologists (1991) advised that forensic assessments should reflect “current knowledge of scientific, professional and legal developments” and examine “the issue at hand from all reasonable perspectives, actively seeking information that will differentially test plausible rival hypotheses” (Section VI (C), 1991, p. 661). In addition, any assessment should “bear directly upon the legal purpose” of the evaluation and provide “support for their product, evidence, or testimony”. Finally, the forensic assessment process should enable communication that will “promote understanding and avoid deception” (Section VII (A), 1991, p. 663). Adding to the validity and the reliability of expert witnesses Rogers, Heilbrun and Otto (2004) highlighted the significance of commercially published facts, tests and scales that are used to aid expert witnesses to testify. This ensures consistency and uniformity. There also has to be an existing available manual to ensure the assessments are applied appropriately, scored correctly and interpreted within the rules. The reliability and validity have to be proven with consistency, repeated testing as well as show proof that tests and assessments are used for the purpose for which they were meant to be used.

However, these standards cannot always be adjusted to the forensic assessments, such failed example is knowing the error rate in child custody evaluation. Forensic assessments such as Sixteen Personality Factor, Personal, Home, Social and Formal Relations Questionnaires, Post Traumatic Stress Diagnostic Scale, Beck Depression Inventory, Personality Questionnaire of Pretoria as well as Wechsler Adult Intelligence Scale and Minnesota Multiphasic Personality Inventory are all mostly based on self-reporting, self-evaluation, interview, psychotherapy or biographical data. It is therefore hard to demonstrate that these assessments are scientific and data reliable enough to be presented in court.