Portside

Part-time faculty at several Boston-area colleges, frustrated by low pay and emboldened by their growing ranks, are taking steps to unionize amid an emerging national movement to give adjunct professors the chance to negotiate better working conditions and benefits.

The broad campaign, spearheaded locally by the Service Employees International Union, successfully unionized adjunct faculty at Tufts University last month, and on Tuesday a vote to unionize at Bentley University lost by just two votes. Organizers have also reached out to part-time faculty at Northeastern and Lesley universities, among other schools.

The push to organize part-time faculty has broad implications for the universities, economic engines for the region that have come to depend on the low cost and flexibility of adjunct faculty as tenure-track positions become scarcer. Well over 40 percent of faculty at private nonprofit colleges and universities in the area are part time, according to the union’s analysis of government figures.

“It’s a method of outsourcing,” said Malini Cadambi Daniel, campaign director for higher education for the SEIU, one of the nation’s largest labor groups.

At individual schools, the reliance on part-time faculty varies but is often striking.

Adjunct faculty made up 64 percent of the faculty at Simmons College, and on the Northeastern campus, part-time professors account for more than half of all faculty, according to data the American Association of University Professors compiled from 2011 federal reports.

At Boston University and Boston College, part-time faculty members account for about 41 percent of their respective faculties, the group reports. About 37 percent of faculty members at Tufts University teach part time.

Some schools say the association’s numbers are inflated or out of date. BC, for example, says one-third of its faculty is part time, while Simmons says half of its faculty is part time.

“There’s a tremendous amount of pressure on colleges to hold down costs of attendance,” said Richard Doherty, president of the Association of Independent Colleges and Universities in Massachusetts. “There is a concern over the cost implications” if adjunct faculty demand higher pay and benefits.

Adjunct faculty members typically earn only a few thousand dollars per course, unlike better-paid tenured professors, and often cobble together a living by teaching at several schools. Most work on contracts from term to term, and a decided minority receives health coverage.

At Tufts, adjunct pay in most disciplines is at least $6,000 per course. BC pays part-time instructors an average of $6,000 per course, and those who have taught four courses per year for five years receive health benefits. But at many schools, the rates can be far lower, specialists say.

“The pay is poverty-level,” said Gary Rhoades, who directs the Center for the Study of Higher Education at the University of Arizona.“They are the working poor of academia.”

The organizing effort is unusual in its focus on private colleges and universities and reflects fundamental changes in college faculties and part-time instructors’ rising discontent.

While common at public colleges, faculty unions traditionally have faced an uphill climb on private campuses unaccustomed to union representation. But the effort has gained momentum as colleges have become increasingly reliant on part-time instructors.

“It’s hard to mobilize mobile labor,” said David Kociemba, president of the adjunct faculty union at Emerson College, which voted to unionize in 2001. “We’re sort of the migrant workers of the Ivory Tower.”

While hesitant to discuss the union push openly, colleges are clearly watching the campaign closely and warily.

Northeastern officials created a website to provide information about the organizing effort, which includes a letter from university provost Stephen Director voicing reservations about the campaign.

“We are concerned about the impact that ceding your rights to do so to an outside organization, which is unfamiliar with our culture, will have on our community,” he wrote.

Officials at Bentley University in Waltham, which says 40 percent of its faculty works part time, said the school does not believe it is necessary for adjunct faculty to take such a step because they are represented on the Faculty Senate.

The vote against forming a union was 100 to 98. In a statement, the union said the outcome was disappointing but would not slow the overall campaign.

In a statement, Bentley said the vote was the right result for the university.

Nationally, the growth in part-time faculty has set the stage for the organizing effort.

In 1989, part-time faculty members were 30 percent of all instructors nationwide. By 2011, that figure had climbed to 41 percent, with graduate students accounting for another 19 percent, according to the AAUP, a professional association that includes a labor union. Just 17 percent of faculty members worked full time and had tenure.

The death of an adjunct professor who had taught for 25 years at Duquesne University in Pittsburgh has served as a rallying point for the campaign. Margaret Mary Vojtko, who died last month at 83 after battling cancer, had no health insurance and was nearly penniless.

Colleges point out that part-time faculty members are not expected to do research, serve on university committees, or have other responsibilities outside the classroom. Many teach just a course or two a year outside their primary career.

Part-time instructors at the state’s public colleges and universities are already unionized. At Massachusetts community colleges, two-thirds of all courses are taught by part-time faculty members. But while wages have risen, part-time instructors do not receive health insurance.

Adjunct faculty members at private colleges are also bracing for a battle over health insurance, saying they fear that colleges will undercut the requirement by limiting their hours, either by capping the number of courses they are allowed to teach or crediting them with fewer hours per course.

That fails to count the many hours instructors spend preparing for class, grading papers, and meeting with students, adjunct instructors say.

William Shimer, a faculty member at Northeastern University, is teaching five business and writing classes at the school this semester, yet is considered part time and does not receive benefits. He said he often does not learn whether he will be teaching until days before classes begin.

“I’ve been told Friday I was teaching a course Monday,” he said.

Deborah Schwartz, a long-time adjunct professor before taking a full-time job at UMass Boston, said part-time faculty members often have to teach so many classes to make ends meet that they cannot give the students as much time as they would like.

Now assistant director of the Adult Literacy Resource Institute at UMass Boston, Schwartz, 50, appreciates the steady paycheck and health insurance. But there is one downside to her new role that she says helps to explain why so many adjunct instructors tolerate the low pay and lack of benefits.

“Boy, do I miss teaching,” she said.

Peter Schworm can be reached at schworm@globe.com. Follow him on Twitter @globepete.