Expert Opinion Exception: s.79 – Requirements

-    An Expert’s Evidence Must First Be Reliable

(1.) The witness must have “specialised knowledge”
–Undefined in Act, so look to the common law
–Three approaches are to be considered
Approach 1: Does the Field of expertise have “general acceptance” (recognition) in the relevant scientific discipline - (Court looks to the scientific community (journals etc) to see if they accept it. If they do then the court will accept it as “specialised knowledge”)
Approach 2: Is evidence from that field of expertise reliable - (Deburt test – Court itself assesses the reliability of the matter and determines whether it is “specialized knowledge”
Approach 3: Hybrid –Recognition is relevant to question of reliability

(2.) Knowledge must be based on witness’s training, study or experience
•    Both conceptual and experiential training can be taken into account
•    Ad hoc experts can also testify (eg. repeated listening to a tape)

(3.) Opinion must be “wholly or substantially” based on that knowledge
•    The expert must stay within his/her area of expertise
•    The testimony must be in admissible form so as to distinguish the assumed facts, to see if they agree with evidence and the reasoning process, to see that expertise is what is being applied and not just common speculation Assumptions: If you put facts as mere assumptions to the witness, s.60 does not make them admissible as evidence of the fact assumed

-    An Expert’s Testimony Must Differentiate Between Facts and Reasoning
•    This makes it possible to answer the question whether it is based on specialised knowledge and to see what is being used is not speculation.

HG v R (1999)
Facts: appellant (HG) convicted of two offences of having sexual intercourse with a child under 10  child was the daughter of his de facto wife
•    Victim lived with natural father and later with her step father HG. Victim made allegations after the event. Victim was referred by a GP to a psychologist, Mr McCromby, who over time, also received info from various other sources including the victim, and came to the conclusion that she had been sexually assaulted in her past by her natural father (not HG). She had effectively blanked out the events involving her natural father, and when certain things happened later in her life, she late developed the idea that HG assaulted her.
•    The qualified psychologist (McCromby) was called, and gave evidence that the child had actually been abused by her real father when she was much younger.
•    Mr HG wanted to call evidence from McCromby. There was no question about his expertise as a psychologist generally.

Issue: Was this opinion based on the expert’s specialised knowledge?
Held: Gaudron J: opinion must be reliable. The ultimate test is reliability.
•    Gleeson CJ:  The psychologist’s opinion was based on a combination of speculation, inference, personal and second-hand views as to the credibility of the complainant, and a process of reasoning which went well beyond the field of expertise of a psychologist  therefore it was not admissible.
•    It is important that the opinions of expert witnesses be confined, in accordance with s79, to opinions which are wholly or substantially based on their specialised knowledge  experts who venture opinion outside their field of specialised knowledge may invest those opinions with a spurious appearance of authority, and legitimate processes of fact-finding may be subverted.  

-    The Expert Must Stay Within his/her Area of Expertise
•    It is OK to partly use common knowledge
•    It is not OK to use non-expert reasoning: HG v R  
•    If the court cannot be sure of this, the evidence is strictly speaking not admissible, and, so far as it is admissible, is of diminished weight: Makita (Australia) Pty Ltd v Sprowles (2001) NSWCA

Expert Opinion Exception: s.79 – The Basis Rule
-    It Is Not Necessary That Evidence Of The Underlying Facts Is Admissible & Relevant
•    At common law, if facts are representations (eg what a patient complained of to the doctor), then:
(a) If they are not disputed or are admissible, they can be used for non-hearsay purpose (s.60) if first-Hand hearsay (Lee v R (1998) HCA)
(b) If they are disputed or unreliable, either:
 s.135 can be used to exclude the evidence
 s.136 Order can be made such that the material not be admitted to prove the fact asserted

Expert Opinion Exception: s.79 –Discretionary Exclusion
-    Even If Admissible, Expert Evidence May Be Excluded On Discretionary Grounds
•    Reliability of the field of expertise, or its applicability to the issue, or the expert’s ability to apply it
•    Extent to which assumed facts are identified and proved
•    Extent of the relevance of the assumed facts
•    Importance of having an expert explain to the jury . If of such common knowledge that it would be a waste of courts time, could be excluded under s135.
•    Importance of the issue
•    Validity of the reasoning process: HG v R

Velevski v The Queen [2002] HCA  (Conflicting expert evidence is to be resolved by the jury, and opinion evidence must be based wholly or substantially upon that knowledge. )
Facts:  Velevski was charged with the murder of his wife and kids while defence argued that the wife had murdered her kids and then slit her own throat.
•    Expert evidence from a number of pathologists was called to determine whether the defence scenario was possible upon examination of the wounds  there was conflicting expert evidence.
Issue: Is there a field of expertise on self-infliction of wounds?  there was also a question of whether the experts gave evidence going beyond their expertise.

Held: Juries are entitled to and are able to evaluate conflicting expert evidence.
•    Per Gaudron J: Where conflicting evidence is based on matters of common knowledge or experience a jury should be able to resolve the issues (evidence of whether wife killed herself was based on common knowledge not expertise)  if it is not, then the jury can only resolve the conflict by looking at other evidence.
•    Also, s80 expressly anticipates that an expert witness can consider matters that are within the common knowledge of ordinary people in formulating an opinion.
•    Per Callinan, Gummow JJ:  While this field is not derived from recognised principles of medical science, it is still capable of being the subject of expert evidence if a suitable foundation for the witnesses training, study or experience can be found.
•    The test for “specialised knowledge” is unresolved. Gaudron J favours the reliability approach and Gummow and Callinan JJ favour the “general acceptance” approach???
•    The court also held that the experts went beyond observation in reaching their opinions  the experts must only use those parts of ordinary knowledge and experience that are necessary in formulating their expert opinions however, the reception of that evidence did not mean that the trial miscarried.

Ultimate issue and common knowledge rules abolished
s80

Evidence of an opinion is not inadmissible only because it is about:
(a)    a fact in issue or an ultimate issue; or
(b)    a matter of common knowledge.

-    The ‘Ultimate Issue Rule’ At Common Law Has Been Largely Abolished By Section 80
•    A psychiatrist, for example, could testify as to a person’s sanity even though that is the very issue the court must decide - witnesses can now use words like ‘negligence’, ‘fraudulence’ etc. in their testimony, subject to:
•    Their ability to so testify
•    Cross-examination
•    Discretionary exclusions
•    Juries being directed to make up their own minds