When friends see Clarissa Marzán, a high-school senior from New York City accepted early to Yale’s class of 2014, doing schoolwork, they often seem confused.

“You got into Yale, why are you worrying about this?” she says they ask her.

But Kikola and other admits to the class of 2014 have an extra motivation to keep up their schoolwork: Every year, the Office of Undergraduate Admissions asks a small number of students to explain significant dips in their spring semester grades. Under rare circumstances, early offers of admission may be rescinded.

Accordingly, of six students interviewed who were admitted this fall, only one admitted to a significant drop in academic motivation. Most early admits said they were just as, if not more, motivated to work hard during their final weeks of high school, and none reported any changes in academic performance. Three college counselors interviewed said while they have encountered cases where their students’ early offers of admission to other universities have been rescinded, students accepted to top-tier colleges such as Yale rarely let their grades slip during their final semester of high school because these students are competing for class rank positions.

Sandy Bean, coordinator of the college and career center at Woodrow Wilson Senior High School, a public high school in Washington, said that students at her school who have been admitted early to highly selective schools such as Yale are now competing to be valedictorian. While grades may slip among the bottom half of the graduating class, Bean said she rarely sees any change in academic performance among the top 10 percent of students.

Michael Cunetta, a senior from Seattle, said he is motivated to keep up his grades because he hopes to graduate first in his class, an honor which requires him to maintain a 4.0 GPA.

But Dean of Admissions Jeff Brenzel said that a small number of admits (he declined to specify exactly how many) do fall prey to “senioritis” each spring. Based on a student’s explanation, the Admissions Office may choose to take no further action, or it may ask the student to take a gap year, recommend additional academic work or even rescind the admission, he added.

What the admissions office regards as a “significant” drop in academic performance varies according to the strengths and weaknesses of each individual applicant, Brenzel said. Typically, acceptable excuses may include ill health, family or school disruptions, or preoccupation with a major engagement or project, he added.

Most of the six early admits interviewed said they hope never to need to explain themselves.

“At first I definitely thought I would fall victim to senioritis, but since I’ve worked hard all of these years, it just wasn’t in my system to be lazy,” said Mia Nishikawa, a senior from Houston. “Although second semester has been busier than first semester, my grades have stayed the same.”

But for Daniel Haziot, who will graduate from Lycée Francois Premier in Paris this year, looking forward to Yale makes keeping up the same amount of effort too difficult.

“I must admit that my efforts dropped considerably in the last months,” he said, though he noted that he has not seen a significant change in grades.

Yale accepted 730 early applicants to the class of 2014. Regular decision applicants will be notified of their application status on April 1.