Expert evidence is necessary in cases where a specialist opinion is required to help the court understand complex medical, psychological, financial or technical issues. Although legal professionals and individuals are free to instruct their choice of expert, the primary duty of an expert witness is to the court. They should act as an independent party and help the court understand the technical or scientific details relevant to their expertise and the case. For expert evidence to be admissible in court it is critical that the expert is unbiased and impartial.

Prior Connections Affect Impartiality

Although expert witnesses are required to supply a statement to verify that they understand their duty to the court and have complied with this duty, bias can still occur. Conflicts of interest arise when an expert has a prior connection to another party involved in the case and this affects their ability to offer impartial evidence. Use of experts who are not independent usually has a negative impact on the whole case, and can result in their evidence being dismissed.

Expert Evidence Can Be Challenged

Experts are under a duty to the court to provide an objective opinion on matters outside the experience or knowledge of the jury, irrespective of any obligations to the instructing party. There are very few circumstances in which expert evidence will be ruled inadmissible, but this does not mean that expert evidence cannot be challenged. The expert’s hypothesis may be tested in cross examination to ensure that it has been subject to scrutiny, and to verify that the expert can support their opinions. If an expert is acting in a biased manner, this will likely emerge after cross examination in court.

The Credibility of an Expert Affects the Outcome

The impartiality of the expert plays a substantial role in influencing the decisions of the court. When courts are faced with several conflicting expert opinions, confidence in an expert’s independence can enable the court to reach an outcome. In a 2015 medical negligence case it emerged that the defendant had a long standing professional relationship with his expert witness, which in turn caused the court to question the credibility of their expert evidence. The High Court judge presiding over this case decided place less weight on the evidence presented by the expert due to their lack of impartiality, and later went on to stress the importance of using independent expert witnesses.

The lesson learned from this case is that if an expert witness is not independent and impartial, it could have a counter productive effect on your case. The judge in the case above was lenient in his decision to still consider the evidence and not dismiss it all together, but none the less it had a negative impact on the case as a whole. At Foresight, we handle the whole process of instructing an expert for you and ensure standards of independence and impartiality are adhered to. We have experts available across the disciplines of psychology, psychiatry, medicine, accountancy and more, so get in touch if you require an expert witness for your case.