Mass. Gen. Laws ch. 31 § 27
Except as provided otherwise by section fifteen, if the administrator certifies from an eligible list the names of three persons who are qualified for and willing to accept appointment, the appointing authority, pursuant to the civil service law and rules, may appoint only from among such persons. If such eligible list contains the names of fewer than three such persons, the appointing authority may appoint from among those persons or may request authorization to make a provisional appointment pursuant to sections twelve, thirteen and fourteen.
If an appointing authority makes an original or promotional appointment from a certification of any qualified person other than the qualified person whose name appears highest, and the person whose name is highest is willing to accept such appointment, the appointing authority shall immediately file with the administrator a written statement of his reasons for appointing the person whose name was not highest. Such an appointment of a person whose name was not highest shall be effective only when such statement of reasons has been received by the administrator. The administrator shall make such statement available for public inspection at the office of the department.
Mass. Gen. Laws ch. 31, § 27