In the first year since Harvard University dropped its early admission program, the number of students who applied to the school grew dramatically.

Harvard representatives said the 18% increase in applicants — to 27,000 for the class of 2012 from 22,955 for 2011 — shows that high school students are responding positively to changes in the university’s admissions process, including the shelving of its early action program and the initiation of a substantial financial aid program for middle-class students. “Students and their secondary school counselors responded positively” to the decision to drop early action, which was “designed to help reduce the frenzy that surrounds college admissions today,” the dean of admissions and financial aid at Harvard, William Fitzsimmons, said yesterday in a statement.

The university announced in fall 2006 that it was ending its non-binding early action program, saying it caused undue stress for high school students and that it favored students from high-income families who did not need to compare financial aid packages.

Instead of spending the fall reviewing early action applications, Harvard admissions officers made extra recruiting visits, including a joint trip with admissions officers from Princeton University and the University of Virginia, two other universities that dropped their early action programs last year, Harvard’s director of admissions, Marlyn McGrath Lewis, said.

“We all could see that we were behind on attracting students from modest backgrounds; plus, we had all this time from giving up early action, so those common denominators made for a natural alliance,” Ms. Lewis said.

Princeton’s application numbers increased by 6% this year.

Most other universities, including New York University and Columbia University, have yet to release their total application numbers, which are still being processed. A Columbia spokesman said the university was crunching the numbers but that the applicant total will not change substantially from last year’s tally.

Other elite universities did release their early admission numbers, and those statistics show that the schools may have benefited from Harvard and Princeton’s decision to abandon their early programs.

Yale University, which has retained its non-binding early action program, experienced a 36% increase in early applications. The University of Chicago and Georgetown University, which also preserved their early action programs, received 45% and 36% more early applications, respectively. The number of early applicants to Columbia increased by 6%, while NYU’s early applications did not change from last year.

“I think that probably Princeton and Harvard’s decision had something to do with the increase, but I couldn’t speculate on how much of the increase was attributable to that,” the dean of undergraduate admissions at Yale, Jeffrey Brenzel, said.

The dean of admissions at the University of Chicago, Theodore O’Neill, said Harvard was “brave” to shelve its early action program but his school saw no problems with its early action program.

“We are comfortable with it. We were comfortable and are even more comfortable now that we’ve been challenged to investigate the program to see if there were any obvious imbalances or preferences for high-income students,” Mr. O’Neill said. “We found, upon investigation, that the early action students were slightly more likely to apply for need-based aid and slightly more likely to get it than regular applicants.”