The arbitrator initiates the hearing by swearing in the parties and witnesses who will testify. The parties then give opening arguments and present both documentary (usually written) and testimonial (oral) evidence. The attorneys are allowed to question witnesses and the arbitrator may ask questions if necessary. Rebuttal questions are also allowed. In some systems, the parties can have a Document Hearing, where the arbitrator studies the paperwork or electronic documents submitted by each party, makes a decision and issues an arbitration award. Or the parties may opt for a Participatory Hearing where each party submits evidence and appears before an arbitrator who studies the evidence , makes a decision, and issues an arbitration award. The arbitration decision or “award” is legally enforeceable and often reviewable by the courts.