The Massachusetts Public Interest Research Group (MASSPIRG) is one of the largest of the state Public Interest Research Group (PIRG) organizations, a series of left-of-center policy research and advocacy groups that operate under the national U.S. Public Interest Research Group (US-PIRG). Both US-PIRG and MASSPIRG fall under the umbrella of the Public Interest Network (PIN), a collection of over one hundred left-wing non-profit and for-profit organizations headed by Doug Phelps, a powerful Democratic Party political operative connected with the Democracy Alliance network of left-of-center donors. 
MASSPIRG initially started as a college campus-based organization after left-wing activist (and later Presidential candidate) Ralph Nader, alongside lawyer Donald Ross, sought “to put into place a model based on the work of their book Action for a Change: A Student’s Manual for Public Interest Organizing.”  It quickly evolved into a state PIRG, which Nader envisioned to be “grassroots lobbying groups for progressive legislation.” 
The Massachusetts Public Interest Research Group (MASSPIRG) is a left-of-center advocacy group that is the Massachusetts state-based arm of the U.S. Public Interest Research Group (US-PIRG), a national organization that oversees a federation of state progressive advocacy groups also known as “PIRGs.”
MASSPIRG initially started as a college campus-based organization after left-wing activist and former Presidential candidate Ralph Nader, alongside lawyer Donald Ross, sought “to put into place a model based on the work of their book Action for a Change: A Student’s Manual for Public Interest Organizing. With Nader serving as founder and Ross visiting college campuses for recruitment, the concept of public interest research groups, or PIRGs…[came] to fruition.” 
Over time, the college campus-based PIRGs became “state PIRGs with Minnesota, Oregon, New York, and Massachusetts becoming the first states to do so.”  Nader envisioned these state PIRGs to be “grassroots lobbying groups for progressive legislation,” and MASSPIRG evolved into one of the largest state PIRGs in the country and received its charitable status in 1974.
MASSPIRG, alongside other left-of-center organizations such as the US-PIRG and the canvassing services group Fund for the Public Interest, is part of the Public Interest Network (PIN), an umbrella organization which controls over one hundred left-wing nonprofit and for-profit organizations. 
Despite the group employing 331 individuals in the 2014 calendar year, only $210,548 in expenses for salaries, employee benefits and other compensation was paid, of which just under $50,000 went to compensation for officers, directors, trustees, and key employees. 
MASSPIRG also sent millions of dollars in grants to multiple organizations also within the Public Interest Network, including $2,524,489 Environment Massachusetts in 2009, a total of $974,291 to the US-PIRG Education Fund between 2006 and 2013, a total of $249,091 to the US-PIRG between 2004 and 2011, and a total of $785,514 to the Fund for the Public Interest between 2004 and 2014. 
Alongside the Fund for the Public Interest and the U.S. Public Interest Research Group Education Fund, MASSPIRG invested in the Denver, Colorado-based investment advisory service firm, Paradigm Partners in 2015.  Douglas Phelps founded Paradigm Partners, which is also a member of the Public Interest Network.
MASSPIRG called for an overturn to the Citizens United v. Federal Election Commission Supreme Court decision of 2010.  The case involved Citizens United, a right-of-center non-profit organization which sought to air and advertise a film critical of the 2008 Democratic Party candidate Hillary Clinton. To do this would have violated the 2002 Bipartisan Campaign Reform Act (BCRA) which prevented corporations or labor unions from creating and releasing “electioneering communications” that refer to a candidate running for federal office within 30 days of a primary election and within 60 days of a general election. 
The Supreme court decided under the free speech act of the First Amendment, the government is prohibited from restricting independent expenditures used for political communications by labor unions, corporations, and non-profit corporations. According to MASSPIRG executive director Janet Domenitz, the Supreme Court ruling was an “egregious decision.” 
MASSPIRG has lobbied for various environmentalist policies including the “100% Renewable Energy” campaign, which seeks to convert the University of Massachusetts system to exclusively environmentalist-approved energy by 2050. 
The consumer group also claimed responsibility for the scheduled shut down of the Pilgrim Nuclear Powerplant, stating that MASSPIRG “has worked for decades to close Pilgrim down and we celebrated the announcement in September 2015 that its official shut down has been scheduled for 2017.”  The power plant closed in 2019 due to “poor market conditions, reduced revenues, and increased operational costs.” 
MASSPIRG regularly performs voter registration and mobilization drives on college campuses for its “New Voters Project,” including in 2018 when a coalition of student organizations at the University of Massachusetts pushed the student body to vote.  The coalition consisted of the Cannabis Reform Coalition, the Center for Education Policy and Advocacy, the Student Government Association’s executive branch and Social Justice and Empowerment Committee, the UMass Democrats, the local student chapter of MASSPIRG, and the UMass College Republicans. 
Critics have noted that the transition of money between Student PIRGs and State PIRGs is deliberately confusing and lacking in transparency.  Some have also said student PIRG chapters “scam” students into funding them, as each time a college student registers for a class they are automatically billed money which is funneled directly into the student PIRG chapter. This money is then directly sent to the state PIRG that governs the student chapter. It has been estimated that PIRG nationwide “causes take in somewhere between $10 and $20 million annually from college students, most all of it unwittingly.” 
The Weekly Standard’s Mark Hemingway noted that although “PIRG tactics may vary across the country… It is fair to say that PIRG organizing everywhere has a shady reputation, even among those who would otherwise be the ideological compatriots of PIRGs.” 
The MASSPIRG student chapter states that students “vote to fund MASSPIRG through a small $9-$11 per-student per-semester waivable fee.” 
According to the University of Massachusetts Lowell’s Office of Student Affairs, more than 11,000 students were billed with only 300 waiving the fees in 2018. 
Phelps is also the president and executive director of the left-wing organizing entity known as the Public Interest Network (PIN), and the president and chairman of the board for US-PIRG. He is also chair of the advisory board of the Fund for the Public Interest. 
Phelps is a founding member of the Colorado Democracy Alliance, the Colorado branch of the Democracy Alliance, a collective of left-of-center donors that has been active in orchestrating “the activities of a permanent ‘left infrastructure’” since 2004.