Case study: the importance of adequate expert witness qualifications

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Ibrahimi & Ors v Commonwealth of Australia (No 3) [2016] NSWSC 1438


This case concerned an incident off the coast of Christmas Island in which several persons travelling on a Suspected Illegal Entry Vessel (SIEV) were injured or killed. The plaintiffs in this case were a group who contended that they suffered loss and damage as a result of the incident and the actions of the Commonwealth of Australia. One of the key issues at trial was whether the Commonwealth owed the plaintiffs a duty to take reasonable care to avoid foreseeable harm to the passengers on board the SIEV.

The plaintiffs sought to rely on an expert report written by Roderick Douglas Pike, a marine specialist with experience in high speed craft, to which the Commonwealth objected. The Commonwealth objected to the report on various grounds, including the fact that Mr Pike had:

  • Expressed his opinion on sea conditions based on a weather report provided to him, whereas the nature of sea and weather conditions is a material fact and not an area of expertise of Mr Pike;
  • Failed to outline the reasoning process from which he obtained the opinions he expressed; and
  • Failed to provide a source for certain formulas he used as part of his expert evidence. He also failed to disclose who developed the formula, the nature of the formula, how the formula was used to prepare relevant calculations, or the basis of the calculations.

Relevant Law

The admission of the expert report was governed by section 79 of the Evidence Act 1995 (NSW):

“79 Exception: opinions based on specialised knowledge

(1) If a person has specialised knowledge based on the person’s training, study or experience, the opinion rule does not apply to evidence of an opinion of that person that is wholly or substantially based on that knowledge.

(2) To avoid doubt, and without limiting subsection (1):

(a) a reference in that subsection to specialised knowledge includes a reference to specialised knowledge of child development and child behaviour (including specialised knowledge of the impact of sexual abuse on children and their development and behaviour during and following the abuse), and

(b) a reference in that subsection to an opinion of a person includes, if the person has specialised knowledge of the kind referred to in paragraph (a), a reference to an opinion relating to either or both of the following:

(i) the development and behaviour of children generally,

(ii) the development and behaviour of children who have been victims of sexual offences, or offences similar to sexual offences.”

Furthermore, in Makita (Aust.) Pty Ltd v Sprowles[1] (and approved by the High Court in Dasreef Pty Limited v Hawchar[2]), the NSW Supreme Court set out the following principles in relation to the admissibility of expert evidence:

  • if evidence tendered as expert opinion evidence is to be admissible, it must be agreed or demonstrated that there is a field of specialised knowledge;
  • there must be an identified aspect of that field in which the witness demonstrates that by reason of specified training, study or experience, he or she has become an expert;
  • the opinion expressed must be wholly or substantially based on the expert knowledge of the witness;
  • so far as the opinion is based on facts observed by the expert, those facts must be identified, and their admissibly proved, by the expert;
  • so far as the opinion is based on assumed or accepted facts, they must be identified and proved in some other way;
  • it must be established that the facts on which the opinion is based form a proper foundation for such opinion;
  • there must be a demonstration or examination of the scientific or other intellectual basis of the conclusions reached. In other words, the evidence must explain how the field of specialised knowledge in which the witness is expert by reason of training, study or experience, and on which the opinion is wholly or substantially based, applies to the facts which are assumed or observed, so as to produce the opinion which is propounded;
  • if all of these matters are not explicit, it is not possible to be sure whether the opinion is based wholly or substantially on the expert’s specialised knowledge; and
  • if the court cannot be sure of that, the evidence is strictly speaking not admissible. So far as it is admissible, it is of diminished weight.”


The court decided that certain parts of the expert report of Mr Pike should be excluded.  


The court agreed with various submissions of the Commonwealth which supported excluding components of the report. These submissions included that:

  • Mr Pike was not a meteorologist and his “opinions” regarding wind speed and wave height were not grounded in relevant training, study, and experience which entitled him to express such opinions. Furthermore, these issues were questions of fact, and not issues requiring expert evidence.
  • Mr Pike’s evidence included an interpretation of meteorological reports which were not authored by him; such interpretation did not involve the “application of specialised knowledge based upon training, study and experience”. Additionally, drawing conclusions from such reports is a question of fact for the court, and not an expert witness.
  • Mr Pike’s evidence did not disclose a reasoning process which was utilised in forming such opinions.
  • Mr Pike failed to disclose the reasoning process upon which his evidence was based including a failure to explain the source of a formula used in providing expert opinions.
  • Opinions expressed on certain issues went beyond the expertise held by Mr Pike. For example, Mr Pike expressed opinions concerning the preferred manner in which to position and launch certain vessels when his expertise lay in the construction and capabilities of vessels.
  • Various opinions given by Mr Pike were irrelevant to the issues at hand.

In handing down its reasons, the court noted that a “fundamental requirement” for the admissibility of expert opinion is that the reasoning process on which the evidence is based is explained by the expert. Mr Pike had failed to do so in various aspects of his report.


The court’s decision in this case demonstrates the strict requirement that opinions given by expert witnesses must be wholly or substantially based on the expert’s training, study, or experience. This case serves as a sound warning to experts and legal counsel that expert reports must deal with the relevant issues at hand and must not consider questions of fact, which are to be remitted to the court for consideration. This case also demonstrates the importance of grounding all expert opinion in sound reasoning and explanation. The consequences of failing to satisfy these requirements, as seen in this case, can be substantial, with large portions of the expert witness report being declared inadmissible. Expert witnesses and legal counsel should ensure that they keep these requirements in the forefront of their minds when drafting and reviewing expert witness reports to ensure that expert witness reports are fully admissible in court.

[1] (2001) 52 NSWLR 705

[2] (2011) 243 CLR 588

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