Cal. Ed. Code § 87675
The arbitrator shall conduct proceedings in accordance with Chapter 5 (commencing with Section 11500) of Part 1 of Division 3 of Title 2 of the Government Code, except that the right of discovery of the parties shall not be limited to those matters set forth in Section 11507.6 of the Government Code but shall include the rights and duties of any party in a civil action brought in a superior court under Title 4 (commencing with Section 2016.010) of Part 4 of the Code of Civil Procedure. In all cases, discovery shall be completed prior to one week before the date set for hearing. The arbitrator shall determine whether there is cause to dismiss or penalize the employee. If the arbitrator finds cause, the arbitrator shall determine whether the employee shall be dismissed, the precise penalty to be imposed, and whether the decision should be imposed immediately or postponed pursuant to Section 87672.
No witness shall be permitted to testify at the hearing except upon oath or affirmation. No testimony shall be given or evidence introduced relating to matters that occurred more than four years prior to the date of the filing of the notice. Evidence of records regularly kept by the governing board concerning the employee may be introduced, but no decision relating to the dismissal or suspension of any employee shall be made based on charges or evidence of any nature relating to matters occurring more than four years prior to the filing of the notice.
Ca. Educ. Code § 87675