The Massachusetts Nonprofit Sector
This older 2005 research report from MassINC, was sponsored by the Mellon Charitable Giving Program/Alice P. Chase Trust, The Boston Foundation, the University College of Citizenship and Public Service at Tufts University. Still worth reading. Its "research finds that the nonprofit sector is among the largest in the nation, employing more than 13 percent of the state’s workforce – nearly double the national average." Summary and link to PDF here.