Substantive law consists of the statutory and case law setting forth rights and obligations upon which a controversy is based, whereas procedural oradjective law states the rules by which a person can secure his or her substantive rights. Thus, procedural law consists of the rules of procedure or practice according to which the substantive law is administered. Procedural law deals with pleadings, which are papers that pass between the parties;practice, which refers to the conduct of litigation; and evidence, or the admissibility of evidence to achieve fairness while avoiding unnecessary expense or delay.
Although procedural law does not state the law, it outlines the procedures that must be followed in applying the substantive law. Procedural law enables the attorney to decide whether a case should go to federal or state court. It will tell the attorney when a lawsuit must be started, what pleadings are required of all parties, and what kind of evidence can be presented at trial. Procedural law can be as important as the substantive law in determining the outcome of a case because a case may be thrown out if the proper procedures are not followed.