Even if a proposal to build two new residential colleges is approved, the undergraduate student body may not grow by a corresponding amount, University administrators said.

The new colleges now under discussion may be used to alleviate housing shortages in existing colleges in addition to increasing the size of Yale College, officials said. While this decision may not be made for several years, as construction will not begin until the college renovations are completed, administrators said they will study the issue as plans for the potential colleges continue to unfold.

University President Richard Levin said he hopes to have a decision by December 2007 on whether or not new colleges will be built.

Levin and Yale College Dean Peter Salovey spoke with the Council of Masters last week about how new colleges could affect the undergraduate population. Morse College Master Frank Keil said the meeting was the first time the issue had been raised with the council.

Norma Thompson, acting master of Berkeley College, said the ideal scenario as discussed at the meeting would relieve the housing shortage, bring more graduate students into the college system and increase the size of Yale College “by a small number.”

“Why not address all issues at the same time?” she said in an e-mail.

Lloyd Suttle, deputy provost for undergraduate and graduate programs, said the building of new residential colleges would probably not lead to a proportional increase in the number of undergraduates.

“My guess is that we will increase the size of the student body by something less than the total amount of additional housing, so that crowding in the existing colleges can be relieved,” he said in an e-mail.

Reducing overcrowding is not the only option administrators have if two colleges are added without a corresponding increase in admitted students. Moving all freshmen off Old Campus and into the individual colleges was another possibility mentioned at the Council of Masters meeting last week, Ezra Stiles College Master Stuart Schwartz said. Old Campus could be turned into graduate housing or classroom space, he said.

Suttle said how to use the additional space is one of a broad set of questions that will be examined as part of the planning process. The process will include studying how many students lived in each college and off-campus historically.

New colleges would not be built until after all the existing ones have been renovated, Suttle said, so any expansion of Yale College is at least six years away. Deputy Provost Charles Long said the possible effect of new residential colleges on Yale College admissions would not need to be determined early in the process.

Some masters and students said new colleges could relieve overcrowding in the existing ones, but others said they do not think overcrowding is a problem.

Jonathan Edwards College Master Gary Haller said overcrowding can be difficult to quantify.

“If you compare it to the kind of space imagined when the college was built, we have about twice as many students now,” he said. “But compared to other institutions, maybe it’s too generous. I don’t know what the reference we should take is.”

Haller said he favors using space in the proposed new colleges to reduce the populations of existing ones, which will give students a real choice between living on campus and off campus. That choice should not have to be based on students’ inability to have the type of room they want on campus, he said.

Jonny Dach ’08, who “wholeheartedly” supports the addition of two new colleges, said half of the new beds created by the new colleges should be used to alleviate annexing and overcrowding in the existing colleges.

“It’s unacceptable for numbers in a hat to condemn junior Elis to a year of exile on Park St. or diaspora around the Old Campus,” Dach wrote in an e-mail. “At least one new college is needed to humanely handle current levels of enrollment, let alone a 10 percent increase.”

But Spencer Sherwin ’08, a Jonathan Edwards student who was annexed to McClellan Hall this year, said he does not mind being annexed and does not think any new colleges need to be used to alleviate overcrowding.

“What I like about having two additional colleges is it just gives more spots for people to become Yale students,” he said. “I don’t feel at this point that the other colleges are overcrowded.”

Davenport College Master Richard Schottenfeld said while it is important that all students have the option to live in the colleges, Davenport does not face the same housing shortages that some other colleges do. After Silliman students move back into their renovated college next year, Davenport and Pierson students will likely move into the Arnold Hall annex on Elm St., which is connected to Davenport by a walkway. Schottenfeld said the new building — which he considers more an extension of Davenport than an annex — is not necessarily a sign of current overcrowding.

Levin said now is an appropriate time to revisit the possible expansion of Yale College, an idea that has not been considered since a failed attempt in the 1970s.

“As we approach the end of the college renovation cycle, it seemed like the right time to bring this up,” he said. “If we expand and cease to be the most selective college in America, I won’t worry that much.”

Salovey said many conversations need to be held before the University decides to build new colleges.

“Before any decisions about expansion are made, you can expect a period of intense scrutiny of all considerations and an opportunity for input from many different perspectives, including that of students,” he said.

Not admitting the equivalent of two new colleges would decrease the number of additional faculty members and classrooms needed to support a student body expansion, Long said. Ramamurti Shankar, chairman of the physics department, has previously said he was approached by an administrator about the effects of a 10 percent increase in the student body, or about 530 students. The average college has about 440 students.