Burden of proof

More colloquially, burden of proof refers to an obligation in a particular context to defend a position against a prima facie other position.

Balance of probabilities

Also known as preponderance of the evidence, this is the standard required in most civil cases. The standard is met if the likelihood that the proposition is true is more likely than it not being true. Effectively, the standard is satisfied if there is more than 50% chance that the proposition is true. Lord Denning in Miller v. Minister of Pension described it simply as "more probable than not."

Beyond a reasonable doubt

This is the standard required in most criminal cases. This means that the proposition must be proven to the extent that there is no "reasonable doubt" in the mind of a reasonable person (usually this means the mind of the judge or jury). There can still be a doubt, but only to the extent that it would be "unreasonable" it assume the falsity of the proposition. The precise meaning of words such as "reasonable" and "doubt" are usually defined within jurisprudence of the applicable country.

The difference between the criminal and civil standards of proof has raised some interesting cases, most notably of O.J. Simpson. Cleared by the criminal trial of murder, the civil trial later ordered substantial damages against him, in effect concluding that he was guilty of murder.

Legal uses

In jurisprudence, the burden of proof is the concept of holding one party to a dispute or one side of a debate responsible for producing a prima facie case. If this party fails to produce a valid case, the decision will go against them, without requiring any further evidence or discussion.

• Burden of proof
• * Burden of production
• * Burden of persuasion
• ** Measure of proof

The burden, therefore, initially lies with the plaintiffs in a case, and not on a defendant who would need to prove that something did not happen. Adequate evidence can, however, shift the burden of proof to the other party.

Criminal law

In criminal cases, the burden of proof is often on the prosecutor. The principle that it should be is known as the presumption of innocence, but is not upheld in all legal systems or jurisdictions. Where it is upheld, the accused will be found innocent if a valid case is not presented.

For example, if the defendant (D) is charged murder, the prosecutor (P) bears the burden of proof to show the jury that D did murder someone.

• Burden of proof: P
• * Burden of production: P has to show some evidence that D had committed murder
• ** e.g. witness, forensic evidence, autopsy report ...
• ** Failure to meet the burden: the issue will be decided as a matter of law (the judge makes the decision), in this case, D is presumed innocent
• * Burden of persuasion: if at the close of evidence, the jury cannot decide if P has established with relevant level of certainty that D had committed murder, the jury must find D not a murderer
• ** Measure of proof: P has to prove all the elements beyond a reasonable doubt
• *** The witness did see D fired the gun, that bullet did come from D's gun, D did pull the trigger, the gun shot did kill the victim ...
  

  Practice

Civil law

In civil law cases, the "burden of proof" requires the plaintiff to convince the trier of fact (whether judge or jury) of the plaintiff's entitlement to the relief sought. This means that the plaintiff must prove each element of the claim, or cause of action, in order to recover.

The burden of proof must be distinguished from the "burden of going forward," which simply refers to the sequence of proof, as between the plaintiff and defendant. The two concepts are often confused.

Other uses

Outside a legal context, "burden of proof" means that someone suggesting a new theory or stating a claim must provide evidence to support it: it is not sufficient to say "you can't disprove this".

Taken more generally, the standard of proof demanded to establish any particular conclusion varies with the subject under discussion. Just as there is a difference between the standard required for a criminal conviction and in a civil case, so there are different standards of proof applied in many other areas of life.

The less reasonable a statement seems, the more proof it requires. The scientific consensus on cold fusion, for example. The majority believes this can not really work, because believing that it would do so would force the alteration of a great many other beliefs about thermodynamics.

A classic example comes from Criswell's final speech at the end of Ed Wood's Plan 9 from Outer Space: "My friends, you have seen this incident, based on sworn testimony. Can you prove that it didn't happen?". Considering that the incident in question involved grave robbers from space, the burden of proof is being incorrectly assigned.

See also