A phased retirement program introduced last December has roughly doubled the number of professors who have ended their academic careers.

The number of professors who either retired or opted for Yale’s Faculty Phased Retirement Plan — which was made available to tenured professors over the age of 65 in December 2010 — was roughly double the University’s typical annual retirement rate and about triple the rate seen in the previous two years, Provost Peter Salovey said. Of those professors, 22 selected the plan through a one-time enrollment opportunity offered to faculty members over age 70, according to Deputy Provost for the Social Sciences and Faculty Development Frances Rosenbluth. Though administrators have committed to holding the Faculty of Arts and Sciences to its current size, Salovey said the vacancies left by those professors will help Yale to bring in fresh academic perspective.

“The goal is not at all to force anyone to retire, rather it is an opportunity to renew the faculty,” Salovey said Thursday.

The faculty retirement program offers professors of eligible ages with at least a decade of tenure the opportunity to cut their teaching and administrative workloads by 50 percent for three years while earning, on average, 75 percent of their salaries. Professors must completely retire by the fourth year, though they may opt to stop working in any previous year. Faculty members are also eligible for a semester of leave sometime during the three-year period, which Salovey said further reduces those professors’ workload during that period.

The program also created a new research professor position that allows any fully-retired faculty member to continue working at Yale if he or she procures funding from grants external to the University, Salovey said.

Rosenbluth said in a Wednesday email that the retirement program has made it easier for faculty to take steps toward retirement. She said a number of factors impact the retirement decisions of faculty members, including concerns for their financial futures and difficulty with letting go of their teaching and research. But she said older faculty are also aware of the need to make room for new hires and facilitate “institutional renewal.”

Such renewal has been particularly relevant to the University’s faculty ever since administrators decided to stall faculty growth in the wake of the nationwide 2008 economic crisis. As Yale’s finances recovered slowly from a nearly 25 percent plunge in the endowment, administrators pledged to hire only to replace departing professors or fill pre-existing vacancies in departments where the need was greatest.

Though Professor Emeritus Werner Wolf did not enroll in a phased plan when he retired in 2001, he said these retirement programs help encourage faculty to end their careers at the University. During his time at Yale, Werner said some faculty members continued receiving their full salaries even though they had declined significantly in productivity.

“Some people may find it useful,” Wolf said. “It certainly sounds like quite a good program.”

Still, not all professors eligible for the program have chosen to take advantage of it.

Giuseppe Mazzotta, a professor in the Italian Department, said he is eligible for the new program but chose not to participate because he thinks he still has an important role within his department, and wants to continue counseling the PhD students he has worked with in recent years. Mazzotta said he does not anticipate taking part in the program in the future because he plans to simply retire when he feels ready to leave.

The phased retirement program announced last December replaced a similar program that had also reduced a professor’s academic obligations by 50 percent, but only offered a 50 percent salary for three years, Deputy Provost for Academic Resources Lloyd Suttle said.

There are currently 691 assistant, associate and full professors in the Faculty of Arts and Sciences.