Tenured members of the Faculty of Arts and Sciences will now be eligible for paid leave twice as often as in the past, Dean of the Faculty William C. Kirby announced in a letter to the Faculty before winter recess.

The change, set to take effect next fall, will allow faculty to take one semester of paid sabbatical after six semesters in residence. Under the current policy, professors must teach 12 semesters at Harvard before they can get a semester of paid leave.

According to Kirby, the changes are a necessary step to ensure that Harvard remains on the vanguard of educational quality.

“I am excited at the potential for this new policy to reinvigorate faculty research,” Kirby wrote in the letter.

He said an increase in faculty research opportunities would benefit the Harvard community as a whole and will “refresh and enliven the teaching of our undergraduates and graduate students.”

With the revised policy, Harvard will join many other universities that currently have more liberal leave policies.

“Anybody who has ever been at another university knows Harvard’s policy is not up to standard,” said Jay H. Jasanoff, chair of the Department of Linguistics.

In his letter, Kirby wrote that revisions would in fact bring Harvard’s “policies to the forefront in comparison with peer institutions.”

The new policy will be implemented over the next four years, accelerating the rate at which faculty members can earn credit toward sabbatical.

Once on leave, faculty may take one semester at full pay or a year at half-pay, in keeping with current policy.

Under the new policy, if faculty remain at Harvard for a full 12 semesters without taking leave, they will qualify for a full year’s sabbatical at full pay.

To address potential problems that may arise from the new policy, such as the disruption of department curricula, Kirby will mandate that each department submit “a three-year curricular plan that incorporates anticipated senior faculty leaves.”

Dean of Undergraduate Education Benedict H. Gross ’71 said he does not think an increase in faculty leaves will have a negative impact on students and their course options.

The three-year plans will allow administrators to ensure that all the basic courses are covered before the leaves are approved, Gross wrote in an e-mail.

“These plans include department contributions to the Core and to the Freshman Seminar program, as well as courses for their concentrators,” Gross wrote.