Balance of probabilities CASES

In English civil procedure, the balance of probabilities is the standard of proof. A fact is treated as proved if, in light of all the evidence, it is more likely than not to have occurred. The court’s task is binary: it decides whether something did or did not happen. If the evidence is evenly balanced, the party who bears the burden of proof fails on that issue.

Definition and principles

The standard asks whether the proposition is more probable than its alternative. There is one civil standard, even for serious allegations such as fraud or dishonesty. The seriousness of an allegation does not raise the legal threshold, but it often means that more cogent evidence is required before the court is persuaded that it is more likely than not. Judges weigh all sources—contemporaneous documents, objective data, reliable expert evidence, and the inherent probabilities—recognising that honest recollection is fallible. The court may draw reasonable inferences from primary facts, but speculation is not enough.

Burden of proof

The claimant generally carries the persuasive burden on each element of the cause of action. A defendant carries the burden on any affirmative defence (for example, consent, limitation, or statutory justification). Evidential burdens can shift as the case unfolds: once a party adduces evidence capable of proving a fact, the evidential onus may pass to the other side to answer it. The legal (persuasive) burden remains where the substantive law places it.

Common examples

• Negligence: the claimant proves duty, breach, causation and loss on the balance of probabilities; if competing causal mechanisms are equally likely, causation is not established.
• Fraud and dishonesty: still the civil standard, but the court usually requires particularly convincing evidence before finding fraud more likely than not.
• Professional discipline and regulation: most bodies apply the civil standard when deciding facts, while ensuring fair procedures and giving clear reasons.
• Inquests and public law fact-finding: where a tribunal or court must resolve disputed facts (for example, certain inquest conclusions), the civil standard ordinarily applies.

Legal implications

• Equipoise: if the evidence is exactly balanced, the party with the burden loses on that issue; close cases turn on detail and credibility.
• Cogency and inherent probability: allegations that are inherently improbable require stronger evidence to satisfy the same standard; this is a matter of weight, not a higher threshold.
• Exceptions: some proceedings (for example, civil contempt leading to committal) apply the criminal standard. Do not assume the civil standard applies without checking the forum and remedy.
• Documents vs memory: well-kept contemporaneous records usually carry significant weight compared with later recollection; expert evidence must be reasoned, not assertion.
• No “percentage awards” for liability: liability is yes/no at this standard. Probabilistic percentage assessments arise in valuation of loss of a chance, not in deciding whether past facts occurred.

Practical importance

For claimants, build the case around reliable documents, objective measurements, and logically structured expert reports; avoid relying solely on witness memory for key points. For defendants, identify gaps and alternative explanations that are at least as likely as the claimant’s account, test the internal consistency of the evidence, and show why inherent probabilities favour your version. Both sides should plead clearly, identify who bears the burden on each issue, and ensure that the evidence matches the pleaded case.

See also: Standard of proof; Burden of proof; Fraud and dishonesty (civil); Loss of a chance; Causation; Expert evidence; Contempt of court.