Mary Perera by her tutor Marisa Perera v Alpha Westmead Private Hospital Pty Limited t/as Westmead Private Hospital

In the case of Mary Perera by her tutor Marisa Perera v Alpha Westmead Private Hospital Pty Limited t/as Westmead Private Hospital, the plaintiff sought compensation for injuries sustained by her daughter, Mary, during a medical procedure. The dispute centred on the admissibility of expert evidence that the hospital sought to exclude from the trial. The matter was heard in the Supreme Court of New South Wales. The court had to determine whether the evidence provided by the plaintiff's expert witnesses was admissible under the Evidence Act 1995 (NSW). The primary legal issue was whether the expert evidence complied with the requirements of section 79 of the Act, which pertains to the admissibility of opinion evidence. The court considered whether the expert evidence was based on facts or assumptions that were shared or accepted by the expert's profession and whether it was necessary for the resolution of the proceeding.

The court found that the evidence presented by the plaintiff's expert witnesses was inadmissible. It was determined that the experts had not based their opinions on facts or assumptions that were shared or accepted by the relevant profession, as required by section 79 of the Act. The court also noted that the evidence was not necessary for the resolution of the proceeding. The court relied on the principles established in Makita v Sporules, where the High Court held that expert evidence must be based on a body of knowledge or experience that makes it more likely than not that the opinion is correct. The court concluded that the expert evidence in this case did not meet these criteria and was therefore inadmissible.

The court ordered that the expert evidence presented by the plaintiff be excluded from the trial. This ruling significantly impacted the plaintiff's case, as the expert evidence was a critical component of her claims. The decision underscores the importance of ensuring that expert evidence adheres to the statutory requirements for admissibility, particularly in cases involving complex medical procedures and the interpretation of specialised knowledge.