At a rally on Beinecke Plaza last month pushing for unionization, leaders of the Graduate Employees and Students Organization boasted that they had support from two-thirds of Yale graduate students.

At the rally’s end, GESO President Aaron Greenberg GRD ’18 carried a large banner bearing hundreds of faces — the faces of the students GESO claims support the group’s efforts  — into Woodbridge Hall. Yet questions persist about whether GESO actually has majority support from graduate students, and about how GESO gathers that support. Some graduate students interviewed said GESO members use aggressive tactics to find new members, and while many graduate students interviewed said they support graduate student unionization, some were less supportive of GESO’s campaign methods.

“I have experienced aggressive approaches at times,” said Emine Altuntas GRD ’17. “At times GESO members were not open to criticism and taking ‘no’ as an answer.”

Altuntas, who said she does not support GESO’s mission to unionize, added that while she appreciates the concerns GESO members have raised about graduate student life and working conditions, she disagrees with the tactics they use.

From 2012 to 2013, Altuntas was an active participant in GESO, but she broke off ties after seeing how extreme the group’s approach was, she said. Altuntas also suggested that GESO may claim to have majority support because the organization accepts graduate student signatures even when those graduate students are only saying ‘yes’ to get rid of GESO organizers and end the conversation.

“They are extremely aggressive,” said Jacob Blumoff GRD ’17, recounting two specific encounters he had with GESO members. When Blumoff came out of class one day, a GESO member that Blumoff did not know approached him, recognizing him by face and name. From this, Blumoff said he realized that the GESO member had memorized his photo, published online by the physics department. Blumoff described the encounter as “mildly creepy.”

On another occasion, Blumoff said he had to tell a GESO representative five times to leave his lab space.

“He was having none of it,” Blumoff said of the representative.

An English graduate student, who asked to remain anonymous because most students in his department are GESO supporters, said that GESO’s “No Intimidation” slogan — a response to perceived intimidation tactics by the office of the dean of the graduate school — is ironic because GESO uses intimidating tactics of its own. GESO members follow people into bathrooms, go to students’ homes uninvited and contact potential supporters repeatedly by email, text or phone, the student said.

GESO has a hierarchical structure whereby more junior recruiters report to GESO leaders in a bottom-up fashion, the student continued, calling it an “aggressive recruitment machine” which puts pressure on people to conform and support their graduate student peers.

“[GESO] is an exploitative ‘boys club’ that tries to justify its practices for a greater good,” the student said.

The University administration has also expressed concerns about GESO’s aggressive tactics. Faculty of Arts and Sciences Dean Tamar Gendler said she and her colleagues have heard numerous complaints about union organizers’ inappropriate recruitment tactics. Gendler said this behavior includes harassing and intimidating, cornering students in laboratories, unwanted visits to student homes and other forms of peer pressure.

Other students, like Robby Blum GRD ’18, said that while some degree of annoyance is expected from an organization with GESO’s ambitious mobilization, the biggest problem with GESO is the way members treat former organizers after they choose to leave the organization. Blum said many of his acquaintances previously helped organize for GESO, but then chose to spend less time with GESO and more time working on their Ph.D. theses. In almost every case, Blum said, GESO’s response to the student was to “bother them constantly to get them to come back.” He added that his friend experienced emotional manipulation over text with a GESO organizer.

“It is set up to chew up and spit out its organizers in a really unhealthy way,” Blum said.

Even beyond critiques of GESO’s tactics, some graduate students said they disagreed with GESO’s mission of obtaining a graduate student union through an election in the first place.

Despite his two-thirds claim, Greenberg has not released the exact number of GESO supporters. In an email to the News, Greenberg said the Oct. 15 banner delivered to Woodbridge Hall bore over two thirds of the nearly 2,000 graduate student teachers and researchers on campus. But Greenberg’s tally of the total number of graduate researchers conflicts with the roughly 3,000 enrolled at the Graduate School of Arts and Sciences and 4,000 at professional schools reported by the Office of Institutional Research. Greenberg did not answer questions about GESO’s methods for determining these figures.

But Nikita Bernardi GRD ’16, who is British and said graduate student unions are commonplace in England, said she was “shocked that there wasn’t a union here.”

“[GESO] has every right to do what is necessary to get a vote,” Bernardi said.

Blumoff said Yale graduate students are well paid and cared for compared to students at other schools. Yale also has channels of communicating with the administration through the Graduate Student Assembly and the Graduate and Professional Student Senate, whose leadership meets with top Yale administrators on a regular basis, he added. Blumoff said he has no desire to tie his needs to those of members of other unions like Locals 34 and 35, which work closely with GESO.

“[GESO] seems to me that they want a union for the sake of having a union,” he said.

Despite four rallies from GESO over the past 18 months, three graduate and professional students out of eight interviewed had never heard of GESO. Paloma Caro FES ’16, who was one of these three, said professional school students like herself can be isolated from students at GSAS.

GSA Chairwoman Elizabeth Salm GRD ’18 said the GSA has no official position on the unionization of the graduate student body, adding that some GSA representatives are also GESO members.

GESO was founded in 1990.

Victor Wang contributed reporting.