Onus of proof: A duty placed upon a civil or criminal defendant to prove or disprove a disputed fact.
Burden of proof can define the duty placed upon a party to prove or disprove a disputed fact, or it can define which party bears this burden. In criminal cases, the burden of proof is placed on the prosecution, who must demonstrate that the defendant is guilty before a jury may convict him or her. But in some jurisdiction, the defendant has the burden of establishing the existence of certain facts that give rise to a defense, such as the insanity plea. In civil cases, the plaintiff is normally charged with the burden of proof, but the defendant can be required to establish certain defenses.
The different onuses of proof for the Criminal and Civil Courts:
• Criminal Courts require proof beyond all reasonable doubt, meaning it has to be 99% factual evidence or proof.
• Civil Courts only require proof which has a balance of probability, meaning the evidence or proof has more than a 50% probability.