The total number of ladder faculty in the Faculty of Arts and Sciences dropped from 722 to 712 between 2011 and 2012, a 1.4 percent contraction in the size of the faculty, according to the 2012 FAS Annual Report released last Thursday.

This marks the first decrease in ladder faculty numbers in more than a decade, although FAS spokesperson Jeff Neal wrote in an email that administrators consider this a “one-year fluctuation.”

According to the report, the size of the FAS has expanded each year since at least 2003, though growth stalled following the 2008 financial crisis, with FAS growing by one member annually between 2009 and 2011. The report suggests that the drop is a delayed consequence of the FAS retirement package, first offered at the end of 2009. Fifteen senior faculty members retired during the 2011-2012 academic year, more than twice the average of six retirees in the preceding five years.

Administrators said that the sharp increase in the number of faculty retirees, although not wholly expected, is a result of the phased nature of the retirement plan, which allows faculty to gradually reduce their responsibilities over two to four years.

With the effects of phased retirements becoming more pronounced, some graying departments are scrambling for faculty search authorizations from the FAS dean to replenish their ranks. Near Eastern Languages and Civilizations, Romance Languages and Literature, and Human Evolutionary Biology are just a few of the departments who have lost or will lose senior faculty. Chairs from all of these departments said they are at some stage of the faculty search process.“

Generally, [FAS] Dean [Michael D.] Smith and Peter Marsden, the dean of social sciences, have listened to the case that we’ve made for renewing our faculty, and they have been responsive,” said Government Chair Timothy Colton, whose department anticipates three retirements by the end of this year. Colton has been authorized to undertake three searches—two for junior and one for senior faculty.

“Our big priority is renewal—hiring younger faculty members,” he said.

While departments vie for more search authorizations, Harvard is not always the top choice for recruits, and the report conceded that searches in the Sciences and at the School of Engineering and Applied Sciences had an unexpectedly low yield.

Of FAS’ 43 ladder faculty offers last year, 25 have been accepted to date. It is not uncommon for new hires to defer their appointments, and only 14 of those hired last year began work this fall.

And maintaining the highest intellectual caliber is prioritized over filling vacancies. Departments whose searches prove unsuccessful can get second chances, “precisely to avoid this pattern of hiring somebody who’s not of the highest quality,” Colton said. “[Smith] won’t promise, but he says that no request for reauthorization to do it again will be unreasonably denied.”

As in past years, departments have also been affected by faculty departures to other universities. The economics department, for example, lost three senior faculty to Stanford.

The annual report was first presented to the faculty in an email and reviewed at this month’s Faculty Meeting. While the average age of faculty has increased from 55 to 57, the gender balance and ethnic composition remain fairly constant, with men outnumbering women in ladder faculty positions three to one and minorities representing seventeen percent of ladder appointments.

—Staff writer Radhika Jain can be reached at radhikajain@college.harvard.edu.

—Staff writer Kevin J. Wu can be reached at kwu@college.harvard.edu.