William Klein’s story may sound familiar to his fellow graduates. After earning his bachelor’s in history from the College at Brockport, he found himself living in his parents’ Buffalo home, working the same $7.25-an-hour waiter job he had in high school.

It wasn’t that there weren’t other jobs out there. It’s that they all seemed to want more education. Even tutoring at a for-profit learning center or leading tours at a historic site required a master’s. “It’s pretty apparent that with the degree I have right now, there are not too many jobs I would want to commit to,” Mr. Klein says.

So this fall, he will sharpen his marketability at Rutgers’ new master’s program in Jewish studies (think teaching, museums and fund-raising in the Jewish community). Jewish studies may not be the first thing that comes to mind as being the road to career advancement, and Mr. Klein is not sure exactly where the degree will lead him (he’d like to work for the Central Intelligence Agency in the Middle East). But he is sure of this: he needs a master’s. Browse professional job listings and it’s “bachelor’s required, master’s preferred.”

Call it credential inflation. Once derided as the consolation prize for failing to finish a Ph.D. or just a way to kill time waiting out economic downturns, the master’s is now the fastest-growing degree. The number awarded, about 657,000 in 2009, has more than doubled since the 1980s, and the rate of increase has quickened substantially in the last couple of years, says Debra W. Stewart, president of the Council of Graduate Schools. Nearly 2 in 25 people age 25 and over have a master’s, about the same proportion that had a bachelor’s or higher in 1960.