Definition of Inadmissible
Inadmissible evidence is evidence such as documents, exhibits, and testimony which is not considered material or relevant to the case at hand. A judge typically has broad discretion in determining whether evidence is admissible, and rule of evidence varies by jurisdiction. For instance, evidence which is cumulative (duplicative) of previously introduced evidence may be excluded. Judges can also exclude evidence which they view as prejudicial, which can mislead the jury or which is considered an unwarranted consumption of court time.
Other factors may also make evidence inadmissible in court. For example, evidence which is seized illegally without a search warrant or without probable cause may not be allowed. If evidence is going to be provided by a witness it may not be allowed if the witness is shown to not be a credible source of the evidence. Testimony which is hearsay may also not be admissible.
Expert testimony may also be reviewed to determine whether or not it is admissible in court. The U.S. Supreme court in Daubert v. Merrell Dow Pharmaceuticals, Inc. outlined the requirements for expert testimony. They are: (1) whether the evidence has been subject to scientific testing and, if so, what methodology was used; (2) whether the evidence has been reviewed by peers or a scientific publication; (3)what is the known potential rate of error; (4) is the evidence generally accepted in the scientific community.