Admissibilitet

Admissibilitet refers to the principle in law that determines whether evidence, documents, or testimony may be presented before a court. It governs what the trier of fact is allowed to consider when deciding a case and is a central concern in both civil and criminal proceedings. Admissibility is distinct from the weight or credibility of evidence; evidence can be admissible but still be weak or unreliable.

Most legal systems base admissibility on rules of evidence that require relevance and reliability. Evidence must have probative value and not be prejudicial, confusing, or duplicative. It must be properly authenticated, and for physical or digital items, a chain of custody may be required. Hearsay, which is secondhand information, is typically excluded unless an exception or exclusion applies. Privileged communications and protected categories (for example, attorney–client or physician–patient communications) are often exempt from admissibility.

A separate consideration is the manner of obtaining evidence. In many jurisdictions, evidence obtained illegally or via constitutional violations may be excluded as fruit of the poisonous tree or under suppression rulings, though there are exceptions where the probative value justifies admission or when the violation was minor or inadvertent.

The gatekeeping role of judges—deciding admissibility—varies by jurisdiction. Some systems provide explicit statutory tests for expert testimony; others rely on case law and rules of procedure. Admissibilitet, therefore, reflects both substantive rules and procedural safeguards designed to ensure fairness and reliability in adjudication.