Yale-NUS upperclassmen returned to campus this semester to find some familiar faces gone, as a number of the school’s inaugural faculty have chosen to leave Singapore.

In the four years since its founding, Yale-NUS has successfully attracted faculty from top overseas universities — including Yale, Princeton and the University of Cambridge — with a comparable salary structure, subsidies for faculty housing and children’s education, as well as the chance to be part of the first liberal arts experiment in Asia. A significant proportion of professors joined Yale-NUS while taking leaves of absence from their original posts overseas. Given that such leaves typically last from two to three years, many inaugural faculty — who attended training at Yale in 2012 before joining Yale-NUS — were recently confronted with the question of whether to stay or return to their previous professorships elsewhere.

This fall, Yale-NUS has a new dean of faculty, and has begun searching for a new president since the college’s inaugural president, Pericles Lewis, announced in July that he will depart in 2017. As a result, many challenges of faculty retention will fall on the shoulders of the college’s new leadership.

“It’s one thing if you are Yale and are trying to pull someone from some other places. It’s another thing if you are at Yale-NUS. It is a new institution and in that sense, a harder sell,” Charles Bailyn ’81, Yale-NUS’s inaugural dean of faculty and the recently named head of Benjamin Franklin College, said.

The considerations involved in a stay-or-leave decision for non-Singaporean faculty vary from person to person, Bailyn said. For example, some professors prefer that their children receive their education in the United States rather than in Singapore, thus leaving the school after a few years. Others enjoy the expatriate lifestyle and opt to stay, he added.

Martin Weissman, a professor of mathematics who joined Yale-NUS at its opening, faced such a choice. Hired by the University of California, Santa Cruz in 2006, Weissman took a three-year leave and moved to Singapore in 2012. He went with the possibility of staying long-term, even selling his house in the U.S. And though he said he enjoyed his time at Yale-NUS, Weissman eventually returned to UCSC this fall.

“My decision was a mix of personal and professional reasons,” Weissman told the News. For example, at UCSC, it is relatively easier to travel and collaborate with mathematicians at many other institutions.

Weissman is not alone: almost all of Yale-NUS’s faculty come from abroad, making the school more likely to experience fluctuations in faculty retention. Around half of those who came to Yale-NUS on leave from other institutions ultimately choose to stay, Bailyn said.

To retain professors, Yale-NUS’s new Dean of Faculty Steven Bernasek said he is committed to enabling the development of faculty, including by providing support for faculty research, offering field studies for faculty and expanding laboratory space and research facilities.

Besides the international makeup of the faculty, however, the young school also has a higher proportion — around two-thirds — of untenured faculty who are more likely to move around.

According to Bailyn, Yale-NUS’s junior faculty members — assistant professors without tenure — naturally move around at the beginning of their careers.

However, Bailyn said he expects the situation to change because many of the school’s inaugural professors, who are already in their fourth year as junior faculty, will be considered for promotions to tenured positions in yearly batches starting this fall.

Lewis told the News in July that the school was trying to recruit more Singaporean citizens and permanent residents for faculty positions. He also noted that professors who start their careers at Yale-NUS are more inclined to stay in the long run.

According to Bernasek, the school launched a Career Postdoctoral Fellowships program this fall targeted at local scholars who have completed their Ph.D.s or postdoctoral work at select international institutions. The fellowships allow Singaporean scholars to carry out their research with a current Yale-NUS faculty member, while also teaching at the school. These scholars may then be eligible for junior faculty openings after one or two years.

“It’s not so much that we expect those people to end up working at Yale-NUS. It’s about building up the talent pool more generally,” Bailyn said. One of the issues that Bailyn noticed during his tenure was that Singaporeans scholars tend not to go into humanities fields, which makes recruiting local talent more difficult.

Still, some Yale-NUS students interviewed do not see faculty retention as a cause of concern.

Although some international faculty are clear about returning to overseas institutions at the outset, Pratyush More YNUS ’18 said the school should continue to attract such scholars who may come only for transient periods, as they bring refreshing outside perspectives.

Adrian Stymne YNUS ’17 said he is not surprised that Yale-NUS faculty, many of whom hail from the U.S., choose to return to their home country after a period of time. He added that the school has handled the turnover well.

“Each faculty member leaving also means a new faculty member joins. We are a small school, and so the turnover expands the range of courses,” Stymne said.