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 Delaware, evidence is regulated by the Delaware Rules of Evidence, which are similar to the Federal Rules of Evidence. These rules dictate that evidence, whether in physical or digital form, must be relevant to the issues in a legal dispute 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 whether that fact is of consequence in determining the action. Expert witness testimony is subject to additional scrutiny; it must be provided by a qualified expert, and the testimony must be based on sufficient facts or data and be the product of reliable principles and methods that the expert has applied reliably to the facts of the case. The judge acts as the gatekeeper in determining the admissibility of evidence, including the reliability of expert testimony, before it is presented to a jury or considered in a bench trial.