Mass. Gen. Laws ch. 211 § 3
The supreme judicial court shall have general superintendence of all courts of inferior jurisdiction to correct and prevent errors and abuses therein if no other remedy is expressly provided; and it may issue all writs and processes to such courts and to corporations and individuals which may be necessary to the furtherance of justice and to the regular execution of the laws.
In addition to the foregoing, the justices of the supreme judicial court shall also have general superintendence of the administration of all courts of inferior jurisdiction, including, without limitation, the prompt hearing and disposition of matters pending therein, and the functions set forth in section 3C; and it may issue such writs, summonses and other processes and such orders, directions and rules as may be necessary or desirable for the furtherance of justice, the regular execution of the laws, the improvement of the administration of such courts, and the securing of their proper and efficient administration; provided, however, that general superintendence shall not include the authority to supersede any general or special law unless the supreme judicial court, acting under its original or appellate jurisdiction finds such law to be unconstitutional in any case or controversy. Nothing herein contained shall affect existing law governing the selection of officers of the courts, or limit the existing authority of the officers thereof to appoint administrative personnel.
Mass. Gen. Laws ch. 211, § 3