Prior Service is a period of a member’s employment with an eligible employer before that employer’s entry date into this System. In most cases, prior service is granted free of charge to all eligible members only if their employer began participating in OPERS on or before January 1, 1975. Proof of such service must be verified in writing by the Retirement Coordinator of each participating employer from payroll and personnel records on file in their office. Prior service may be purchased at actuarial cost by a member for employment with a participating employer that occurred prior to the date the agency joined OPERS if the agency joined after January 1, 1975. (See Purchasing Service).