941 C.M.R. 2.03
(1) Membership.
(b) For those employees whose initial service with the MSERS commences on or after July 1, 2009 membership in the MSERS requires an employee as defined in M.G.L. c. 32 to:
(k) For employees whose hours of employment do not initially allow for membership in the MSERS but whose weekly work hours fluctuate, membership may be established in accordance with 941 CMR 2.03. Additionally, the following criteria must also be met:
(m) For purposes of 941 CMR 2.03, a "per diem" employee shall be an individual who is employed by the Commonwealth or other employing entity participating in the MSERS on a non-permanent, intermittent, less than full-time, or ad hoc basis, with or without an employment contract, compensated with pay earned on a per diem basis, and who works without basic employment benefits. For retirement purposes, per diem employees may include individuals appointed to serve on boards and commissions, and for whom a statute may or may not provide a stipend to be paid to compensate them for this service. Unlike a benefitted employee, a per diem employee is:
(2) Creditable Service.
(d) Educational Collaboratives/Regional Vocational and Technical High Schools.
(e) Sabbaticals.
(f) M.G.L. c. 32, § 26(3)(a).