Yale received 4,820 early applications this year for the class of 2012 — 36 percent more applications than last year, Dean of Undergraduate Admissions Jeff Brenzel said Tuesday.

The surge in applications may be a reaction to decisions by Harvard and Princeton universities last year to discontinue their early-admission programs, which left high-achieving high-school students with fewer early options, admissions experts said, although Brenzel declined to attribute the increase to any one factor. Brenzel said it is too soon to know how many students Yale will accept and how the increase in applications will affect Yale’s yield.

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Last fall, Yale received 3,541 early applications, down 13 percent from the previous year. The five remaining Ivy League schools and Stanford had not released their early application numbers as of Tuesday.

Because of the changes in the admissions landscape Harvard and Princeton effected by canceling their early programs, it will be difficult to predict how many students will accept early-admissions offers from Yale this year, Brenzel said.

As a result, he said, Yale will likely continue to be cautious in its early admissions offers to avoid accepting too many early applicants, leaving room for qualified applicants in the regular admissions cycle. Last year, Yale accepted 709 students early, or 19.7 percent of those who applied.

Brenzel said he does not expect Yale to accept fewer applicants than last year but does not know before the admissions officers read the applications whether or not Yale will accept more.

“The last two years, we have been conservative in our offers to avoid the potential for overcrowding, and we have been happy to go to our wait list for some outstanding students,” Brenzel said. “I expect to be conservative in the same way this year.”

Yale offers a single-choice early-action option for students that is non-binding, as Harvard did until this year. Princeton formerly offered a binding early decision option.

Yale College Dean Peter Salovey said he will refrain from forming conclusions about admissions trends until the end of this application cycle.

“It would be irresponsible to speculate about the reasons for the rise in early applications this year until we know whether regular applications increased, decreased, or remained the same,” he said in an e-mail. “It seems to me that any explanation will require both pieces of data.”

The increase in early applications to Yale may be partially explained by an influx of would-be applicants to Harvard and Princeton, said David Petersam, president of the Virginia-based AdmissionsConsultants Inc., which guides about 1,000 high-school students through the college-admissions process each year.

Most students who look at Harvard or Princeton also consider Yale, Petersam said. Many of his students are determined to apply somewhere early, so Yale’s non-binding early action program is an attractive option, Petersam said.

“Since they really can’t apply to Harvard or Princeton yet, they’re definitely a little more likely to apply to Yale early,” he said.

High-school students who applied to Yale this year are worried by the large numbers, several guidance counselors interviewed said.

Students at the private Harvard-Westlake School in Los Angeles are particularly concerned that it will be more difficult to gain acceptance to Yale early because the greater volume of applications will result in a lower acceptance rate, Harvard-Westlake college counselor Beth Slattery said.

Among the rumors flying around the hallways is speculation — not based on any concrete evidence — that Yale will cope with a possible lower yield by giving increased preference to legacies because they might be more likely to come, Slattery said.

Brenzel said the legacy rumor is unfounded and that the admissions office has no set acceptance rate in mind.

The number of students from Harvard-Westlake applying early to Yale is about the same as it was last year, Slattery said. She said this consistency surprised the college counselors, who expected students’ college strategies to change after Harvard and Princeton dropped their early programs.

Regardless, Slattery said she expects that students — at least from Harvard-Westlake — will continue to matriculate at Yale at a rate comparable to previous years’.

“Yale is consistently among the most popular schools with Harvard-Westlake students,” Slattery said. “For most of the kids in the applicant pool, it really is their first choice.”

The final number of early applications may increase slightly as the admissions office enters applications received by mail into the computer system, Brenzel said. This year, 93 percent of early applications were submitted online, he said.

Yale will notify early applicants of its decisions sometime on or after Dec. 14.