With a 55 percent increase in early applications, the percentage of early applicants admitted to Yale fell from 21.3 percent last year to 16.6 percent this year, Dean of Admissions Richard Shaw said Monday.

This year, Yale accepted 670 students from an early applicant pool of 4,046. Last year, 2,611 students applied early and 557 were admitted.

Shaw said students who applied early to the Class of 2008 are even more diverse than students from previous classes, possibly because of the switch to single-choice Early Action. The policy change should also lower the University’s yield, Shaw said.

Single-choice Early Action allows students to apply to only one school early but does not require them to matriculate upon acceptance. Under binding Early Decision, some students chose not to apply to Yale because they could not compare financial aid offers from different universities, Shaw said. He said now that students can compare financial aid offers before choosing where to matriculate, a more diverse group can apply early.

Shaw said the increase in applications made this year’s early process more competitive than it was in past years. He said the students admitted early to the Class of 2008 are “quantitatively stronger” than students in previous classes, but he anticipates the overall caliber of the class will be comparable to that of previous ones “when the dust settles.”

Since students admitted early to Yale no longer have to matriculate, the yield is more difficult to predict, Shaw said. He said the Class of 2007 is large, so the Admissions Office is trying not to admit too many students to the Class of 2008. This will minimize the risk of having a matriculating class too large for the University to handle, he said.

“We may have wait-list activity … if the yield diminishes,” Shaw said. “We don’t want to go too high [in regular decision].”

Shaw said his best estimate for early yield is 85 percent.

Undergraduate recruitment committee member Emma VanGenderen ’06 said all the applications kept admissions officers busy.

“I think everyone was pretty stressed,” VanGenderen said. “They receive so many qualified applicants.”

Shaw said it was a busy but manageable time.

“I think we had the capacity to do it, and we did it,” Shaw said.

More application readers were hired, Shaw said, and VanGenderen said undergraduate workers were allowed to work as much overtime as they wanted during the week after the early application deadline.

Undergraduate recruitment coordinator Julia Solomon ’05 said admissions officers appeared more happy than overwhelmed with the application increase.

Solomon said the Admissions Office received a higher volume of e-mails from applicants this year than it had in previous years.

Without a guaranteed early yield, Solomon said she must work harder than ever to recruit admitted students. She said each year the Admissions Office gives her a list of admitted students who would contribute significantly to student life at Yale, academically or otherwise. Now that these exceptional students are not bound to come to Yale even if they are accepted early, she said, the outreach process is even more important.

Solomon said undergraduates usually hold a phone-a-thon in which they call all students admitted under Regular Decision. This year, the phone-a-thon will also include calls to students admitted under Early Action, she said.

Shaw said he expects the final number of applications to the Class of 2008 to be around 19,500.