Generally, only prior service with a New York State or City public employer is creditable. Prior service outside New York State is not creditable (except for Tier I members as outside teaching service). Creditable prior service must meet at least one of the following criteria:

• The service is otherwise creditable and was performed while you were employed in a TRS-eligible position but before you enrolled in TRS (e.g., service as an eligible paraprofessional or as a CUNY adjunct that preceded TRS membership); or
• The service predates your membership in an eligible New York State or City retirement system, but would have been creditable at the time the service was performed had you been a member of that retirement system; or
• Credit was previously granted for the service in an eligible New York State or City retirement system, but you lost your membership rights with that retirement system; or
• The service is otherwise creditable and was performed while you were ineligible for membership in a public retirement system (e.g., service as a substitute teacher performed prior to membership eligibility of the substitute teaching title under the Board of Education Retirement System (BERS)).