The High Court’s decision in Dasreef Pty Ltd v Hawchar  HCA 21 has been significant as the threshold requirements for the admissibility of expert evidence are clarified (French 2012). This essay will first discuss the facts of the case, followed by the technical requirements and perceived difficulties related to expert evidence identified by the court in this case.
Mr Hawchar, the respondent claimed damages from his employer, Dasreef Pty Ltd, the appellant as he was diagnosed with silicosis allegedly caused by the unsafe working environment. An expert, Dr Basden was retained to provide a report centering on the foreseeability of the alleged injury claimed by Mr ...view middle of the document...
In this case, Dr Basden’s opinion was relevant to proving whether or not there were adequate safety measures in the working environment of Dasreef. However, it was used to quantify the numerical exposure in which the estimates provided in the opinion was not based on Dr Basden’s specialized knowledge based on his training, study or experience, as required by s79(1). The majority found that ‘the form of his opinion did not connect the estimate with his relevant specialized knowledge’ and hence not admissible on this basis (Dasreef Pty Ltd v Hawchar  HCA 21 at paragraph 34).
Criteria governing s79(1) of Evidence Act
The majority also identified two criteria that must be satisfied under s79(1) for the evidence to be admissible, these include:
i. The expert has specialized knowledge based on his or her training, study or experience.
ii. The opinion evidence is wholly or substantially based on that knowledge.
The first criterion was addressed in paragraph 37 of the case. By referring to the judgment in Makita (Australia) Pty Ltd v Sprowles  NSWCA 305, in order for the opinion to be admissible, there must be an explanation as to ‘how the relevant field of specialized knowledge applies to the assumed or observed facts to produce the expert’s opinion’ (Dasreef Pty Ltd v Hawchar  HCA 21 at paragraph 37). The second criterion is related to the relevance requirement mentioned earlier, where it is necessary for the expert to demonstrate the connection between his or her expertise and the opinion provided. In other words, the opinion needs to be presented in a way that can explain that it is based on training, study or experience (Dasreef Pty Ltd v Hawchar  HCA 21 at paragraph 36).
The common law requirements
Justice Heydon identified three common law requirements in relation to the admissibility of expert evidence in this case, these include:
i. The facts and assumptions which the opinion is based must be identified (Dasreef Pty Ltd v Hawchar  HCA 21 at paragraph 64).
ii. The facts and assumptions identified must be proved with admissible evidence (Dasreef Pty Ltd v Hawchar  HCA 21 at paragraph 66).
iii. The reasoning process applied by the expert in reaching the conclusion which flows from the facts or assumptions identified and proved (Dasreef Pty Ltd v Hawchar  HCA 21 at paragraph 91).
The first and third...