Burden and standard of proof 

Two questions sit behind every contested fact in a proceeding: who has to prove it, and how convincingly do they have to prove it? These are the questions of burden and standard of proof. They are distinct concepts that are often run together in loose speech, and keeping them separate is essential to reasoning clearly about a case.

The legal burden

The legal burden of proof (sometimes called the persuasive or ultimate burden) is the obligation to satisfy the fact-finder, to the required standard, of the existence of a fact in issue. If, at the end of the case, the fact-finder is not satisfied to the relevant standard, the party carrying the legal burden on that issue loses on that issue. The legal burden generally does not shift during a trial: it is fixed by the substantive law governing the claim or charge and stays with the same party throughout.

In a civil proceeding, the plaintiff ordinarily bears the legal burden of proving the elements of their cause of action, and a defendant bears the burden of proving any matter they positively assert, such as a defence. In a criminal proceeding, the prosecution bears the legal burden of proving every element of the offence. An accused generally does not bear a legal burden of disproving guilt, though in some jurisdictions specific statutory defences reverse the burden onto the accused for that particular issue — such reversals are exceptions to the ordinary rule, not the rule itself, and must be identified in the specific legislation rather than assumed.

The evidential burden

The evidential burden is a different and lesser thing: the obligation to point to, or adduce, sufficient evidence to allow an issue to be considered at all — to get the issue "in play" before the fact-finder. It does not require persuading anyone of anything; it only requires enough evidence that a fact-finder could rationally find in the relevant party's favour on that issue. A party who fails to discharge an evidential burden on an issue loses the ability to have that issue considered, without the legal burden on it ever being tested.

The evidential and legal burdens can rest on different parties for the same issue. A common pattern in criminal proceedings is that an accused carries an evidential burden to raise a defence — pointing to some evidence capable of supporting it — after which the legal burden of disproving that defence, once genuinely raised, falls back on the prosecution.

The civil standard: balance of probabilities

In civil proceedings the applicable standard is the balance of probabilities: the fact-finder must be satisfied that the existence of the fact is more probable than not. It is often described as requiring the scales to tip, however slightly, in favour of the party bearing the burden. Briginshaw v Briginshaw (1938) 60 CLR 336¹ recognises that the strength of evidence needed to reach this state of satisfaction may vary with the gravity of the allegation and the seriousness of its consequences, without altering the standard itself.

The criminal standard: beyond reasonable doubt

In criminal proceedings the prosecution must prove each element of the offence beyond reasonable doubt. This is a markedly higher standard than the balance of probabilities, and deliberately so. The demanding standard reflects the asymmetry of harm the criminal process risks: a wrongful civil judgment can usually be remedied in damages or reversed on appeal, whereas a wrongful criminal conviction exposes a person to loss of liberty, and to the state's moral condemnation, in circumstances that are far harder to undo. The standard is not defined with mathematical precision, and courts are traditionally reluctant to elaborate on what "reasonable doubt" means beyond its ordinary language meaning, but its function is clear: it requires a level of certainty well beyond mere probability before the state may punish.

Applying this in a problem question

1. Identify the fact in issue, and ask separately who bears the legal burden and who bears the evidential burden on it — they may not be the same party.
2. Check whether any statute reverses the ordinary burden for a specific defence or issue in the jurisdiction in question, rather than assuming the default position applies.
3. Identify whether the proceeding is civil or criminal, and apply the balance of probabilities or beyond reasonable doubt accordingly.
4. Do not conflate a party's evidential burden being satisfied with that party having proven the issue — the legal burden and standard still have to be met.
5. Explain why the criminal standard is set higher, if the question calls for that justification, by reference to the asymmetric consequences of error.