Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 43, § 36

Except as provided in this section, if a vacancy occurs in the school committee by failure to elect, or otherwise, the city council and the remaining members of the school committee shall meet in joint convention and elect a suitable person to fill the vacancy until the first Monday in January following the next regular municipal election; and, if there would be a vacancy on said first Monday, it shall be filled at such regular municipal election for the balance of the unexpired term. The mayor, if present, shall preside at the convention.

Whenever under Plan E a vacancy occurs in the school committee by failure to elect, or otherwise, such vacancy shall be filled as provided in section one hundred and two.