An expert witness is an individual with training, knowledge and experience who helps the judge or jury to understand scientific, technical and specialized evidence or facts about to the case. Additionally, experts are often questioned about their opinion that they have developed based on their experience and the facts surrounding the case. It is also the job of the expert witness to teach and explain the basics to lawyers and educate them on issues they are not personally familiar with. With their help, the defense can be built on scientifically accurate information. Expert testimony must be clear and logical, they must speak slowly and clearly, be truthful and as accurate as possible. This essay will draw on psychological theories to critique the role of the expert in forensic assessment and as a witness in court. More specifically, confirmation bias theory, social role theory, and source credibility theory will be discussed in relation to expert witnesses and their testimony. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay Experts are required to have knowledge about a specific issue in question and not just be familiar with the area in general. However, meta-analyses of previous 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 debates about the role and benefits or harms that expert witnesses can cause. The researchers believe that experts need to be more transparent about the significance or insignificance of the results provided. Furthermore, Duquette (1981) highlighted the concern of neglecting or overcompensating for the expertise and experience of experts. One of the key findings of previous research was that one fifth of the expert witnesses who testified were not qualified to provide valid and reliable psychological advice. Many expert witnesses do not focus on reflecting an impartial and independent assessment. However, there are standards that experts must meet to be considered an expert witness. These standards were first presented by Daubert in the late 20th century, serving as guidelines for the judge to decide whether an expert's testimony is admissible or inadmissible and whether it is overall useful or necessary for the testimony. The criteria cover four categories, discussed in Rogers and Johansson-Love (2009) and Shapiro et al. Expert opinion and their expertise must be falsifiable, tested or proven false. There has to be an error rate regarding the facts they are providing. Facts must be peer-reviewed/published and generally accepted by all. The Committee on Ethical Guidelines for Forensic Psychologists (1991) advised that forensic evaluations 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). Additionally, any assessment should “directly impact the legal purpose” of the assessment and provide “support for their product, evidence or testimony.” Finally, the forensic evaluation process should allow for communication that “promotes understanding and avoids deception” (Section VII(A), 1991, p. 663). In addition to the validity and reliability of expert witnesses, Rogers, Heilbrun, and Otto (2004) highlighted,.