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Week 11: Opinion Evidence - Coggle Diagram

- - - - The witness may merely express an opinion about a matter before the court, this is inadmissible.
        The court may make such interpretations itself.
      - The witness may also make an observation interpretation , where the 'opinion' is so much a part of the observation that one does not make sense without the other.
        Observational interpretation is generally permitted.
        
        Sometimes it may not be possible for a witness to say what they saw, without giving some level of interpretation.
        
        I saw my car in the car park.
        I possess my dark blue Subaru Impreza, licence plate 123ABC. I identified that in the car park was a dark blue Subaru Impreza, licence plate 123ABC
      - The use of Non-Expert opinion
        
        Common law permitted the reception of non-expert opinion evidence where it was very difficult for witnesses to convey what they had perceived about an event or condition without using rolled-up summaries of lay opinion - impressions or inferences - either in lieu of or in addition to whatever evidence of specific matters of primary fact they could give about that event or condition
        
        Usual examples are age, sobriety, speed, time, distance, weather, handwriting, identity, bodily health, and emotional state, but a thorough search would uncover many more.
        Lithgow City Council v Jackson [2011] HCA 36
    - - Often judge and jury simply lack sufficient detailed knowledge to enable them to make sense of evidence before them. In these situation, it may be necessary for the court to have the benefit of testimony from an expert.
        
        Such evidence is, of course, opinion. However, it is an informed opinion, conveying expertise which could not otherwise be put before the court.
        
        If matters arise in our law which concern other sciences or faculties, we commonly apply for the aid of that science or faculty which it concerns. Which is an honourable and commendable thing in our law. For thereby it appears that we do not despise all other sciences but our own, but we approve of them and encourage them as things worthy of commendation.
        Buckley v Thomas (1554) 75 ER 182
      - Who is an Expert?
        
        First, there must be 'a body of knowledge or experience which is sufficiently organised or recognised to be accepted as a reliable body of knowledge or experience'.
        R v Bonython (1984) 15 A Crim R 364
        Osland v The Queen (1998) 197 CLR 316
        
        Second, the expertise of the person who purports to be an expert must be established. There is no specific formula for such accreditation, which may be through formal or professional expertise, or through long experience.
        Osland v The Queen (clinical and forensic phsycologist
        R v Harris (Aborginal tracker)
      - What Facts are Considered?
        
        Remember that an opinion - even an expert opinion - is still fundamentally an interpretation applied to a set of facts
        
        For the court to be confident that the expert's opinion is useful, the court must know what facts - proven or assumed - underpinned the evidence of the expert.
        Makita v Sproules [2001] NSWCA 305
        
        Further, those facts must then be capable of being proven in evidence, and if necessary tested by counsel.
        R v Ryan [2002] VSCA 176
        
        If the facts under interpretation by the experts cannot be satisfactorily explained to the court, then how is the court to believe the expert?
      - Questions of Law
        
        'Experts in Law' are not entitled to give their opinion on whether a set of facts meet a particular standard.
        
        The fundamental reason for this is that experts are only used for matters concerning 'other sciences and faculties'. The court has no need of further legal expertise to enable it to perform its functions
        
        However, an appropriate expert can, if necessary, give evidence regarding the content of foreign law. They cannot however, purport to apply those foreign legal standards to the current case: R v Tonkin [1975] Qd R 1
      - Conflict in Expert Testimony
        
        The role of experts is to assist, not to usurp, the functions of the court.
        Thus it is open to the jury to be unpersuaded by the expert evidence.
        
        If expert evidence is received from both sides and the views of the experts conflict, this does not automatically equal 'reasonable doubt'. It is open to the jury to be sufficiently convinced by one expert view, that it no longer entertains reasonable doubt.
        Chamberlain v The Queen (No. 2) (1984) 153 CLR 521
      - The 'Ultimate Issue'
        
        The ultimate issue rule states that experts may not give evidence which goes to the ultimate issue to be determined by the court.
        
        The rule seems odd in principle as:
        
        the finder of fact is fully entitled to reject the expert evidence anyway
        
        expert evidence only goes to the facts; it is still necessary for the court to apply the law
        
        'It is doubtful that there is now an absolute rule precluding an expert witness from expressing a view as to the ultimate issue.'
        Murphy v The Queen (1989) 167 CLR 94
      - Statutory Rules - Expert Reports
        
        Under the Civil Uniform Procedure Rules, expert witnesses generally give their evidence by way of report rather than orally: s 427
        
        Expert Reports must be disclosed to all other parties within a set period: s 429
        
        Experts may then be cross-examined in the same manner as any other witnesses if necessary. The UCPR specifically relate to evidence-in-chief.
        
        Where experts disagree, the court may direct them to meet, identify areas of agreement and disagreement, and try to resolve the areas of disagreement: s 429B