Opinion Evidence Flashcards
What is an opinion?
An opinion is advanced by a witness when the witness testifies to an inference or conclusion drawn, which is a perceived impression of their belief.
Briefly discuss the opinion evidence rule.
- If the court can adjudicate a matter without receiving opinion evidence, such an opinion is inadmissible because it is irrelevant.
- It will be superfluous or supererogatory.
What are the different foundational theories regarding the opinion evidence rule?
- First, opinion evidence is admissible where relevant and inadmissible where irrelevant (superfluous).
- Second, the ultimate issue must be preserved (or retained only for the court to make). The court makes the ultimate finding and not a witness. At times, lay opinion evidence, but more often, expert opinions express the ultimate issue.
- Third, the witness is not permitted to advance an opinion that includes a conclusion of law to the facts or the meaning of words appearing in legislation.
As a practical example, lay opinion evidence may be relevant in which circumstances?
- The age of a person.
- The state of sobriety of a person.
- General condition of a thing.
- The speed of a vehicle.
Discuss the probative value of a lay opinion.
- When the lay opinion is relevant and admissible, it provides prima facie evidence and, if not challenged, it may (as opposed to must) be accepted by the court.
- Much will depend on the individual circumstances of the case and the reasons advanced by the lay witness for forming the opinion.
What are the functions of a expert witness?
- To give evidence of facts (observed facts).
- To give the court an abstract or to provide general knowledge concerning an expert discipline.
- To give evidence pertaining to their own inferences or opinions drawn on the issues before the court and to give reasons (grounds) for such an opinion.
What are the basic rules when it comes to the admission of expert evidence?
- If the expert’s evidence is supererogatory (superfluous) and the court can reach a conclusion/inference without the assistance of the expert witness, the expert evidence is irrelevant.
- The expert opinion becomes admissible where, owing to the expert witness’s skill, experience, and qualification, he/she is better placed than the court to draw an inference/conclusion from the facts.
- When the question is one of science or skill, the expert is permitted to give an opinion, even on the ‘ultimate issue’.
Discuss the foundation that must be laid when an expert witness is introduced.
- The expert must have specialized knowledge and/or training and/or skill and/or experience.
- The expert must indeed be an expert for the purposes for which the expert is called (qualified to express the given opinion).
- The expert must refrain from expressing an opinion in the air (based on hypothetical facts).
When will expert evidence be unreliable?
In JA obo DA v MEC of Health, Eastern Cape, the court said that expert evidence is unreliable if:
- It is based on a misinterpretation of the facts.
- Is speculative.
- Is inherently contradictory and/or inconsistent.
The expert witness may not be biased. Bias may be clear from which factors?
- The expert reaches a conclusion even before accepting the instruction.
- He/she has a financial interest in the outcome of the case.
- He/she is related to one of the parties involved.
- He relies on irrelevant information to support his/her conclusion.
Discuss hearsay of the expert witness.
- The factual input on which the expert rely (collateral input) may not be based on a statement of a person not called as a witness in the trial.
- The expert can provisionally rely on hearsay evidence provided that the hearsay ‘bar’ is later removed.
Discuss the Hollington rule.
The court in Hollington v F Hewthorn held that the opinion of another court is irrelevant to the proceedings of another court.
How is the scope of its application limited in South Africa?
In Institute for Accountability v Public Protector the court tried to limit the scope of the application as follows:
- The rule related to prior criminal proceedings and not prior civil proceedings.
