trial

Trial is a formal examination of evidence before an appropriate tribunal to determine a matter of law or fact. In law, trials resolve whether a person is criminally responsible or whether a civil dispute has merits. Criminal trials decide guilt beyond a reasonable doubt; civil trials determine liability or damages on a balance of probabilities.

Establishing a trial typically involves charges or claims, the right to counsel, and procedural protections designed to ensure due process. The most common formats are criminal trials and civil trials. A bench trial is decided by a judge; a jury trial is decided by jurors, though some systems permit a judge in a jury's place when requested or required by law. The burden of proof and standard of evidence differ: beyond a reasonable doubt in criminal cases; preponderance or clear and convincing evidence in many civil matters.

During the trial, parties present opening statements, call witnesses, submit exhibits, and conduct examinations. The prosecution or plaintiff bears the burden of proof; the defense may contest and present counter-evidence. After closing arguments, the judge charges the jury or resolves the issue in a bench trial. A verdict may result in acquittal, conviction, dismissal, or judgment for the plaintiff; post-trial motions and appeals may follow.

While the term trial most often refers to legal proceedings, it is also used in scientific and medical contexts to describe controlled experiments or clinical trials that test hypotheses, devices, or therapies. Such trials follow ethical guidelines, require informed consent, and proceed through stages (for example, phases I–III) and oversight by institutional review boards and regulatory authorities.

Historically, trials have been central to formal justice systems in many cultures, evolving from early assemblies and adjudications to modern court procedures with rules of evidence and procedural protections.