What does half of every Harvard class have in common?

Besides high test scores and near-perfect grades, they also applied early—and got in—according to The Early Admissions Game, a new book co-authored by two Harvard economists and and a former admissions officer from Wesleyan University.

Selective colleges have long argued that there is no formula or “big secret” in the quest for the coveted letter of acceptance. But Kennedy School of Government economists Christopher N. Avery ’88 and Richard J. Zeckhauser ’62 and former Wesleyan admissions officer Andrew Fairbanks conclude in their new book that applying early can give an applicant an admissions edge equivalent to an increase of 100 points on the SAT.

In the context of an increasingly cutthroat admissions climate, this conclusion is creating ripples among admission officers and high school college counselors.

“Even in draft form, the findings of the book—distilled in broad form—have had an effect on the debate,” says Zeckhauser, who is Frank P. Ramsey professor of political economy. “They will even appear in this year’s version of some college guides.”

Though he and his co-writers had originally hypothesized that applying early did somehow benefit an applicant, Avery, a professor of public policy, says that they were “surprised by the magnitude of the advantage.”

“We didn’t have any grand plan at the beginning,” he says. “We kept deciding to become more ambitious because the answers [to our initial questions] were so interesting.”

Avery says he became interested in studying early admissions in 1996, when Princeton, Stanford and Yale switched from a nonbinding Early Action (E.A.) policy to Early Decision (E.D.), in which students promise to attend a school in exchange for a December admissions decision.

“All of a sudden, applicants had to be strategic about where to apply,” says Avery, who characterizes the book as answering two main questions about the early admissions process. He and his co-writers say they wanted to determine the size of the advantage conferred upon early applicants; they also hoped to determine how much, if anything, potential applicants knew about this advantage.

Applying E.A. boosts an applicant’s chances by 18.9 percent—the same amount that a 100-point jump on the SATs would—according to the book’s statistical analysis of more than 500,000 actual admissions decisions. The effects of applying E.D. are even more drastic, giving an applicant a 34.8 percent boost, which corresponds to a 190-point SAT advantage.

These numbers acquire increased significance in light of the authors’ finding that “there was considerable misunderstanding about how the system works,” Zeckhauser says.

This is particularly true among students from less prominent schools or lower-income families, as the authors’ interviews with hundreds of current and former applicants demonstrated.

“It was startling to me to hear how different students from different backgrounds were in sophistication,” Avery says. “Students from public schools . . . really didn’t seem to know much about the process, even after getting into Harvard.”

Furthermore, the study reveals that colleges play a significant part in the students’ confusion about early admissions.

“A number of colleges dissembled about the way they chose students,” Zeckhauser says. “For example, a number that offered a significant edge to early applicants denied that fact.”