Fewer high school seniors than targeted have accepted their offers to attend Northwestern this fall, prompting the university’s Office of Undergraduate Admission to begin accepting students off the wait list, admissions officials said Tuesday.

About 1,900 students have accepted offers of admission so far — just shy of the 1,925-student target set by the admissions office for the class of 2008, Associate Provost for University Enrollment Rebecca Dixon wrote in an e-mail to The Daily.

NU has not failed to meet its target class size with initial student deposits since the university pegged its freshman class size at 1,925 in 1999.

As a result of this year’s gap, admissions officials have begun drawing from the batch of about 500 wait-listed applicants, Dixon wrote. Although the deadline to accept offers of admission passed May 1, she added, NU still is receiving deposits from some incoming freshman.

NU sent letters of acceptance to fewer students this year — 4,760, down from 4,819 students last year — anticipating a higher percentage of admitted students would accept their offer of admission.

Dixon wrote that university officials expected to dip into its pool of wait-listed students this year, which was almost twice as long as last year’s.

“Since our recent history is one of overshooting the size of the class, we did admit somewhat fewer students than in previous years with a strong hunch that we would use the wait list,” Dixon wrote. “So, the plan seems to be developing just as we had projected.”

But the university has not used the wait list to fill large gaps in a freshman class since 1999. On the contrary, more students than expected have chosen to enroll in recent years. Last spring, almost 1,950 students sent in deposits by this time. The year before saw 2,089. These figures reveal a drop in NU’s yield — an important barometer often used by organizations that rank universities. A school’s yield is the percentage of admitted students who accept their offer to enroll.

In the past, NU occasionally has needed to admit at least a few students off its wait list when some students change their mind during the summer, according to F. Sheppard Shanley, NU’s senior associate director of admission.

But NU is not alone in finding itself with a lower-than-expected yield rate this year, said Boyd Bradshaw, incoming president of the Illinois Association of College Admission Counseling. Rather, it is part of a nationwide trend.

“I would say that, because a university like Northwestern had to go to its wait list, it means that the competition is getting more fierce among institutions,” he said.

College-bound students are applying to more schools than ever before, Bradshaw said. In addition, larger, less expensive schools like the University of Illinois are extending offers of admission to more students. This siphons students away from more expensive private schools like NU, he said.

As a result of these factors, yield rates plummet as more colleges compete for the same pack of high school seniors.

“The concern is that they’re not going to be admitted,” Bradshaw said. “So when it comes time to deposit, the yield rate is not as strong.”

In the future, this fact might lead NU to admit more students in the spring rather than funneling them to the wait list, he said.

Next year’s freshman class also will see more “underrepresented minority students” compared to the class of 2007, Dixon wrote in the e-mail. Slightly fewer international students may join the class of 2008, even though NU received about 100 more applications from foreign students and admitted slightly more than last year.

Dixon speculated that this fact could be due to higher costs or the state of international affairs. But international students probably still will comprise about 5 percent of next year’s freshman class, she wrote in the e-mail.

Scores for the incoming class will be equal to or slightly higher than the class of 2007’s, Dixon wrote. Since NU is still receiving more deposits, Dixon wrote that it was too early to provide more specific details about the incoming class.

Kate Ambash, an incoming Weinberg freshman, said she agonized until the last minute before choosing to attend NU.

Ambash said she was torn between Rice University in Houston and NU. She spent a great deal of time visiting both schools — especially at NU, where in 2003 she attended the Medill School of Journalism five-week summer Cherubs program, part of the university’s National High School Institute.

“There were things I disliked about both schools and there were things I liked about both schools, so it made it really hard,” she said.

Ambash eventually chose NU because of a minor detail. She said she was more pleased with the housing process at NU.

“I love Northwestern,” Ambash said. “It has a great reputation. I know I’ll get a great education.”