Evidence is information that exists in physical or digital form—such as written agreements and e-mail communications—as well as testimony from witnesses who have personal knowledge of facts relevant to a dispute. Evidence generally must be relevant to be admitted in court and considered by the factfinder (judge or jury) in resolving a lawsuit. And some forms of evidence, such as expert witness testimony, must be shown to be sufficiently reliable (as determined by the judge) to be admitted in evidence.

In Nebraska, evidence is regulated by both state statutes and rules of evidence, which are consistent with the Federal Rules of Evidence. Evidence must be relevant to the facts of the case to be admissible in court. Relevance is determined by whether the evidence makes a fact more or less probable than it would be without the evidence, and if that fact is of consequence in determining the action. Physical and digital evidence, such as written agreements and email communications, must be authenticated to be admitted. Testimony from witnesses requires that the witness has personal knowledge of the matter. Expert witness testimony is subject to a reliability standard, which is assessed by the judge. The expert's methodology must be scientifically valid and properly applied to the facts of the case. Nebraska follows the Daubert standard for the admissibility of expert testimony, which requires that the testimony is based on sufficient facts or data, is the product of reliable principles and methods, and that the expert has applied the principles and methods reliably to the facts of the case.