Three common law rules are referred to in relation to natural justice or procedural fairness.
The Hearing Rule
This rule requires that a person must be allowed an adequate opportunity to present their case where certain interests and rights may be adversely affected by a decision-maker.
When conducting an investigation in relation to a complaint it is important that the person being complained against is advised of the allegations in as much detail as possible and given the opportunity to reply to the allegations.
The Bias Rule
This second rule states that no one ought to be judge in his or her case. This is the requirement that the deciding authority must be unbiased when according the hearing or making the decision.
Additionally, investigators and decision-makers must act without bias in all procedures connected with the making of a decision. A decision-maker must be impartial and must make a decision based on a balanced and considered assessment of the information and evidence before him or her without favouring one party over another. Even where no actual bias exists, investigators and decision-makers should be careful to avoid the appearance of bias.
Investigators should ensure that there is no conflict of interest which would make it inappropriate for them to conduct the investigation.
The Evidence Rule
The third rule is that an administrative decision must be based upon logical proof or evidence material. Investigators and decision makers should not base their decisions on mere speculation or suspicion. Rather, an investigator or decision maker should be able to clearly point to the evidence on which the inference or determination is based.