Membership in the Public Employee Retirement System of Idaho (PERSI) is mandatory for all employees who are eligible for membership. The rule of eligibility is normal work assignment of twenty (20) or more hours per week for a five-month period. Normal means half or more of the week during the term of employment. Eligibility for and participation in PERSI is the factor used to establish eligibility for and participation in other benefits such as sick leave, personal leave, holiday pay, and sick leave bank benefits.