Mass. Gen. Laws ch. 18B § 9
The commissioner may appoint and remove such assistant commissioners as the commissioner shall from time to time determine, not to exceed four in number, who shall be assigned to areas of responsibility to be specified by the commissioner.
Each assistant commissioner shall be qualified by training and experience to perform the duties of the office and shall at the time of appointment have received a masters or higher degree and shall have had professional experience of not less than five years as an administrator in a field related to human services or said assistant commissioner shall have had professional experience in a field related to human services for a period of years equivalent to the number of years required to obtain a master's degree, and shall have had, in addition thereto, professional experience of not less than five years as an administrator in a field related to human services. The position of assistant commissioner shall be classified under section 45 of chapter 30 and the salary shall be determined under section 46C of said chapter 30. Assistant commissioners shall devote full time to the duties of the office.
Mass. Gen. Laws ch. 18B, § 9