Under section 76 of the Evidence Act 1995 (Cth), as a general rule, opinion evidence is inadmissible in Court to prove the existence of a fact about the existence of which an opinion is expressed.
However, each court has rules of conduct for the giving of evidence by Experts.
Expert evidence is an exception to the rule, in that it is admissible opinion evidence. Section 79 of the Evidence Act 1995 (Cth) sets out that 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.
What this means is that, for example, a medical practitioner can give evidence about medical issues because they have spent years studying and practicing medicine and their opinion is reliable and probative to be admitted into evidence because of their specialised knowledge and expertise, provided of course they can establish that they have the relevant specialised knowledge, then identify the facts they proceed upon and explain how applying their knowledge to the facts leads to their conclusion.
In Makita (Australia) Pty Limited v Sprowles (2001) 52 NSWR 705 the Court set out six principles for admissibility of expert evidence some of which include:
- The expert witness must have ‘specialised knowledge’
- There must be an identified aspect of the field of specialised knowledge in which the witness demonstrates that by reason of specified training, study or experience, the witness has become an expert;
- The opinion proffered must be ‘wholly or substantially based on the witness’s expert knowledge’;
- The expert’s evidence must clearly identify the facts observed, as well as the assumed or accepted facts, upon which the expert opinion is based, and they must be proved;
- The expert’s evidence must set out the analysis and reasoning employed in order that the conclusions are able to be properly understood (i.e. there is a proper foundation for the opinion expressed).
If the facts or assumptions underlying the opinion evidence are not proved (e.g. if the expert was not properly briefed), this may undermine the expert evidence, resulting in it being inadmissible.
The expert need not amass all the factual data on which the opinion is to be expressed and this task can be delegated to another.
The witness must be available for cross-examination to prove the facts upon which the opinion is based.
When is expert opinion evidence necessary in the Family law Courts?
In the Federal Circuit and Family Court of Australia, expert evidence is required to prove various elements of a party’s case.
Expert evidence is admitted into evidence by virtue of the expert evidence exception under section 79 of the Evidence Act 1995 (Cth).
Expert evidence in family law proceedings, may include:
- Valuation evidence including valuation of a business, shareholding, trust assets, superannuation, and other assets;
- Medical issues relevant to a property settlement matter, for example a person’s current and future capacity to earn, cost of providing various services, a person’s life expectancy; and
- Matters relevant to parenting cases to determine the best interests of children, for example, psychological issues of a parent or a child or recommendations by a social worker/psychologist about the arrangements that are in the best interests of a child having regard to the facts and circumstances of the case.
The Family Law Rules provide for the appointment of an expert at any stage of proceedings on application by a party or by the Court’s own motion. An expert is generally appointed to enquire into and report on an issue arising in the proceedings, that is not a question of law and the court will give directions as to the extent of the opinions sought.
Usually the expert appointed by the Court is agreed upon by the parties and thereafter appointed as court expert, by the Court.
But what about section 69ZT of the Family Law Act in Parenting Proceedings?
The exception under section 79 of the Evidence Act 1995 (Cth) is very strict in that the opinion evidence is only admitted if the person has specialised knowledge based on their training, study or experience and their opinion is wholly or substantially based on that knowledge.
However, there may be other circumstances where a party seeks to have evidence admitted in family law proceedings, which do not satisfy this strict criteria, and the evidence may still be admitted in these circumstances, in parenting proceedings.
This is because, under section 69ZT of the Family Law Act, certain provisions of the Evidence Act 1995 (Cth) do not apply in parenting proceedings.
Under subsection 2, even if the evidence is admitted, the Court is entitled to give such weight as it thinks fit to the evidence, as a consequence of the Evidence Act not applying.
Under subsection 3, the Court may still decide to apply one or more of the provisions of the Evidence Act if the Court is satisfied that the circumstances are exceptional, and; (b) The Court has taken into account the importance of the evidence in the proceedings, the nature of the subject matter in the proceedings, the probative value and the powers of the Court to adjourn the hearing to give directions.
This means that whilst evidence such as Hearsay and opinion evidence may be admitted, it will be given little or no weight by the Court.
It is therefore much more powerful to put evidence in an admissible form and by way of an appropriate witness, in order for it to be given weight by the Court.
Palange & Kalhoun  FedFamC2F 149
The issue for determination by the Court in Palange & Kalhoun was whether the child should be vaccinated against Covid-19. The Mother proposed the vaccination, whereas the Father opposed it, at least for the time being.
In presenting their case, the parties sought to admit several forms of opinion evidence in support of or against their position as to whether the child of the relationship should be vaccinated for Covid-19.
Summary of Evidence Act principles as applied in Palange & Kalhoun
- The only opinion evidence which was admissible in the proceedings under the Evidence Act was Dr E’s opinion in relation to the risks of the Covid-19 vaccination for children aged 5 to 11;
- The other evidence (opinion evidence from mother about child’s health and risks, articles about Covid-19 vaccination safety) was not admissible under the Evidence Act, but was admissible and was admitted by reason of section 69ZT of the Family Law Act (which states that the rules of evidence do not apply to child related proceedings and court may give such weight as it thinks fit to the evidence admitted);
- BUT the Court referred to section 69ZT(3) stating that the Court has the capacity to decide to apply the excluded provisions in the Evidence Act to the proceedings in certain circumstances.
But was the evidence given weight once admitted by the Court? Lets find out….
Opinion evidence of the parties regarding Covid-19 infections, risks + benefits of vaccinations (incl pamphlets), risks to child if not vaccinated, opinion of mother regarding the psychological benefits of vaccination
These opinions would have been excluded by the hearsay / opinion rule, under the Evidence Act 1995 (Cth), but were admitted into evidence by reason of section 69ZT(1) of the Family Law Act.
The Court held however:
- The parties were not medical experts;
- They are repeating what other bodies have said about complex medical and public health issues;
- In absence of relevant qualifications of either party to give opinion evidence regarding these complex issues or child’s psych health benefits, the Court gave no weight to their opinions;
- Regarding the pamphlets attached to their affidavits – without the authors available to be cross examined, no weight was given to them.
Expert opinion evidence of Dr E which was unchallenged and uncontested regarding the risks of Covid-19 vaccination for children 5-11
The Mother obtained expert evidence of Dr E in relation to the risks and benefits of the Covid-19 vaccination for children aged 5 to 11.
The evidence of Dr E was in summary: “while COVID-19 illness is frequently mild in children, the risks associated with infection far outweigh the risks associated with vaccination.”
The Court held:
- The evidence was admissible under s79 of the Evidence Act – he is a highly qualified expert;
- The Father did not take issue with her evidence or object to it, his only concern was the fact that her opinion does not address possibility of presently unknown risks arising in the future;
- The Court noted the father’s comments about the unknown longer term risks arising from the use of a new vaccine in children;
- The Court noted that the Father did not call any evidence of an expert regarding the long term side effects potentially from the vaccine, and the only material in relation to the Father’s concern was his lay opinion;
- In all the circumstances, the Court gave substantial weight to the evidence of Dr E, in making his decision;
- Held that the risks known and quantifiable from Covid-19 infection outweighed any potential unknown risk asserted by the father and that vaccination significantly reduced those risks.
An order was therefore made for the subject child to be vaccinated against Covid-19.
Notation in orders re published advice of public health authorities (n.b. parties did not seek to rely upon this)
Common knowledge is another exception to the opinion rule under section 144 of the Evidence Act (Cth).
Section 144 provides that the opinion rule does not apply to matters of common knowledge in the locality in which the proceedings are held and capable of verification by reference to a document the authority of which cannot be questioned.
Interestingly, the Judge made comments to the effect that information published by public health authorities may be common knowledge under section 144 of the Evidence Act.
In this regard, the Judge had made a notation in interim orders setting the matter down for interim hearing that the judge may take judicial notice of published advice issued by public health authorities including ATAGI recommendations on the Pfizer Covid-19 vaccine used in children aged 5 to 11 years.
The Judge importantly noted that this exception would not have applied to academic articles the Mother annexed to her affidavit, because the issues the subject of those articles were controversial and a variety of differing expert opinions have been provided in relation the issues. The Judge excluded those articles as inadmissible on this basis.
So when is opinion evidence in and when is it out?
In order to maximise the chances of the expert opinion evidence being admissible and being given weight by the Court, we recommend the following:
- Put the evidence in an admissible form, that is, in an affidavit;
- Make sure the opinion is given by the appropriate witness, i.e. the person whose opinion it is (e.g. do not attach a report from your psychiatrist, have your psychiatrist do an affidavit attaching it, as only they can depose to the truth of the contents of the report);
- Make sure the witness giving the opinion has specialised knowledge such that they are qualified as an ‘expert’ to give the opinion, by virtue of their training/study/experience;
- Make sure that the witness is available for cross-examination at trial so that any facts observed by the expert, upon which the opinion is based, as well as any assumed or accepted facts, can be proved;
- Make sure that the expert’s evidence sets out clear analysis and reasoning employed by the expert so as to form a proper foundation for the opinion expressed.
If you have a question about opinion evidence of expert evidence and the admissibility of it in your family law proceedings, contact our office and book a reduced rate initial consultation with one of our experienced Brisbane family lawyers to have a conversation about your individual circumstances.