Expert Evidence
What is expert evidence?
• Matters outside experience of the court
• Expert provides and makes sense of issues in the case
• It is necessary to interpret or makes sense, without it wouldn’t
• Opinion evidence as well as fact evidence
• A meaningful distinction?
• Normally witnesses cannot comment on matters of opinion/speculate
• Expert witness can similarly comments however, but can’t give an opinion on
the ultimate issue e.g. is the driver a competent driver
• Difference between factual evidence and evidence about matters of opinion
• We can question the distinction
• Can be a real risk if juries merely uncritically accept expert evidence and rely on it
too much
• Unduly place too much weight on it
• Therefore law seeks to limit it and the extent it should be used
• Defective expert evidence has resulted in a high number of high profile miscarriages
of justice
• Bc of the court seek to use boundaries
___________________________________________________________________________
Admissibility
• Why limit?
• A) Active case management – adversarial feel, judges is like an umpire who doesn’t
get their hands guilty by interfering
• But they do contribute to active case management
• Get involved in planning case and that it runs to timetable and doesn’t run
too long and take up court time
• Reduce costs and delay
• Desire to narrow down live issues of case
• B) Avoidance of deference to experts – risk of fact finder deferring to experts and
not making an independent judgement on evidence
• Will say expert said this – so defendant must be guilty
• Too much weight given to expert evidence, not making independent
assessment to strength of all evidence
• No healthy skepticism
• Specific statutory provisions – SOME specifically allow for admissibility of expert
decision so not common law discretion of judge
• Obscene Publications Act 1959 – an example, s4 of this act, says justified and
to be used/allowed
• Criminal Procedure (Insanity and Unfitness to Plead) Act 1991 – requirement
of expert evidence in some cases – e.g. criminal law for insanity, if a d pleads
this, a jury cannot make determination that they aren’t guilty in the absence
of expert evidence
, Luttrell [2004] EWCA Crim 1344, approved Bonython [1984] 38 SASR 45
COA in this case –
For expert evidence to be admissible, two conditions must be satisfied: first, that study or
experience will give a witness's opinion an authority which the opinion of one not so
qualified will lack; and secondly the witness must be so qualified to express the opinion
[32].
- So, two parts
- Necessary to have evidence bc witness opinion has authority members of courts
don’t have
- And they are qualified to give it – not just anybody
King CJ (at p.46) said that the question “may be divided into two parts:
(a) whether the subject matter of the opinion is such that a person without instruction or
experience in the area of knowledge or human experience would be able to form a sound
judgment on the matter without the assistance of witnesses possessing special knowledge
or experience in the area, and
(IN SHORT IS THE EXPERT EVIDENCE NECESSARY?)
(b) whether the subject matter of the opinion forms part of a body of knowledge or
experience which is sufficiently organised or recognised to be accepted as a reliable body of
knowledge or experience, a special acquaintance with which by the witness would render
his opinion of assistance to the court” [32].
(SUFFICIENTLY ORGANISED TO BE ACCEPTED) not just any, but recognised – this part
wasn’t explained in Luttrel but approve in Bontython
THIS IS A MAIN PART ^ IN KNOWING WHY
• Three part test
• The evidence must relate to specialist knowledge that is outside of the
court’s and fact finder’s experience;
• The body of knowledge that the expert is drawing upon must be sufficiently
well developed; and
• The expert must be sufficiently qualified.
IN SHORT IT IS THIS^
1. Specialist knowledge
• Necessary to hear the evidence
• Bonython: question is whether the court ‘would be able to form a sound
judgment on the matter without the assistance of witnesses possessing
special knowledge or experience’.
• SO IF MEMBERS OF COURT DO HAVE THIS SUFFCIEINT KNOWLEDGE AND
EXPERIENCE THEN WE DON’T NEED AN EXPERT (e.g. driving we all have)
What is expert evidence?
• Matters outside experience of the court
• Expert provides and makes sense of issues in the case
• It is necessary to interpret or makes sense, without it wouldn’t
• Opinion evidence as well as fact evidence
• A meaningful distinction?
• Normally witnesses cannot comment on matters of opinion/speculate
• Expert witness can similarly comments however, but can’t give an opinion on
the ultimate issue e.g. is the driver a competent driver
• Difference between factual evidence and evidence about matters of opinion
• We can question the distinction
• Can be a real risk if juries merely uncritically accept expert evidence and rely on it
too much
• Unduly place too much weight on it
• Therefore law seeks to limit it and the extent it should be used
• Defective expert evidence has resulted in a high number of high profile miscarriages
of justice
• Bc of the court seek to use boundaries
___________________________________________________________________________
Admissibility
• Why limit?
• A) Active case management – adversarial feel, judges is like an umpire who doesn’t
get their hands guilty by interfering
• But they do contribute to active case management
• Get involved in planning case and that it runs to timetable and doesn’t run
too long and take up court time
• Reduce costs and delay
• Desire to narrow down live issues of case
• B) Avoidance of deference to experts – risk of fact finder deferring to experts and
not making an independent judgement on evidence
• Will say expert said this – so defendant must be guilty
• Too much weight given to expert evidence, not making independent
assessment to strength of all evidence
• No healthy skepticism
• Specific statutory provisions – SOME specifically allow for admissibility of expert
decision so not common law discretion of judge
• Obscene Publications Act 1959 – an example, s4 of this act, says justified and
to be used/allowed
• Criminal Procedure (Insanity and Unfitness to Plead) Act 1991 – requirement
of expert evidence in some cases – e.g. criminal law for insanity, if a d pleads
this, a jury cannot make determination that they aren’t guilty in the absence
of expert evidence
, Luttrell [2004] EWCA Crim 1344, approved Bonython [1984] 38 SASR 45
COA in this case –
For expert evidence to be admissible, two conditions must be satisfied: first, that study or
experience will give a witness's opinion an authority which the opinion of one not so
qualified will lack; and secondly the witness must be so qualified to express the opinion
[32].
- So, two parts
- Necessary to have evidence bc witness opinion has authority members of courts
don’t have
- And they are qualified to give it – not just anybody
King CJ (at p.46) said that the question “may be divided into two parts:
(a) whether the subject matter of the opinion is such that a person without instruction or
experience in the area of knowledge or human experience would be able to form a sound
judgment on the matter without the assistance of witnesses possessing special knowledge
or experience in the area, and
(IN SHORT IS THE EXPERT EVIDENCE NECESSARY?)
(b) whether the subject matter of the opinion forms part of a body of knowledge or
experience which is sufficiently organised or recognised to be accepted as a reliable body of
knowledge or experience, a special acquaintance with which by the witness would render
his opinion of assistance to the court” [32].
(SUFFICIENTLY ORGANISED TO BE ACCEPTED) not just any, but recognised – this part
wasn’t explained in Luttrel but approve in Bontython
THIS IS A MAIN PART ^ IN KNOWING WHY
• Three part test
• The evidence must relate to specialist knowledge that is outside of the
court’s and fact finder’s experience;
• The body of knowledge that the expert is drawing upon must be sufficiently
well developed; and
• The expert must be sufficiently qualified.
IN SHORT IT IS THIS^
1. Specialist knowledge
• Necessary to hear the evidence
• Bonython: question is whether the court ‘would be able to form a sound
judgment on the matter without the assistance of witnesses possessing
special knowledge or experience’.
• SO IF MEMBERS OF COURT DO HAVE THIS SUFFCIEINT KNOWLEDGE AND
EXPERIENCE THEN WE DON’T NEED AN EXPERT (e.g. driving we all have)
