Mass. Gen. Laws ch. 31, § 6C
A civil service employee, except an employee serving during his probationary period, who receives an evaluation with which he disagrees, shall within ten days unless otherwise specified in the collective bargaining agreement, select an option of appealing the results of such evaluation through either the grievance procedure contained in the employee's respective collective bargaining agreement or through the procedures outlined in paragraphs (a) to (c), inclusive.
(c) Within ten days receipt of a decision on an appeal provided for in paragraph (b) the employer or the employee may further appeal the evaluation to the civil service commission. The commission shall, within twenty-one days after the close of such hearing or the evaluation, render a written decision and send notice thereof to all parties concerned.
Saturdays, Sundays, vacation days, and legal holidays shall not be counted in the computation of any period of time specified in this section.