The judicial branch comprises the courts and the judges who preside over them. The roles of courts broadly cover dispute resolution and the interpretation, development and application of the law. In order for a court to have validity it must have the jurisdiction or authority to hear and determine a matter. Most courts operate on an adversarial basis and are independent from the other branches of government. Juries ensure citizen involvement and are seen as a cornerstone of the legal system, although recent reforms have attempted to balance justice with greater efficiency.