The group, the College Board, is sending a package of information on top colleges to every senior who has an SAT or Preliminary SAT score in the top 15 percent of test takers and whose family is in the bottom quarter of income distribution. The package, which includes application fee waivers to six colleges of the student’s choice, will be sent to roughly 28,000 seniors.

The program is the largest response so far to new research showing that most low-income students with high test scores and grades do not even apply to, let alone attend, select colleges. Forgoing significant financial aid, many students may instead enroll in nearby colleges with low graduation rates.

Judith Scott-Clayton, an economist at Columbia who is not involved in the outreach program, said the lack of applicants is one of the rare hurdles in education that could be easily addressed.

“We spend so much time worrying about the kids who are not qualified — that’s actually a pretty hard problem,” Ms. Scott-Clayton said. Low-income teenagers who excel in high school but fail to graduate from college, she said, are “an untapped resource.”

If the new effort succeeds, it may create tensions for some colleges. Many presidents and deans say they want to recruit more low-income students, but failing to do so has long kept their financial aid spending lower than it otherwise would have been.

At Harvard, despite a recent increase in the number of such students, 53 percent of this year’s freshmen come from families making at least $125,000 a year, and 29 percent from families making at least $250,000, according to a survey by The Harvard Crimson student newspaper.

The College Board’s information packets are modeled on those sent in a recent experimentby Caroline M. Hoxby of Stanford and Sarah E. Turner of the University of Virginia, economists whose findings suggested that application fee waivers greatly influenced students’ decisions.

Among high-achieving, low-income students in the experiment who received a packet, 54 percent ultimately won admission to one of the nation’s 238 top colleges; among similar students who did not get a packet, 30 percent were admitted.

“We are at the beginning of a sustained effort to move these numbers substantially,” said David Coleman, the president of the College Board, who has called the issue his top priority. Critics of the College Board have argued that its standardized tests bias the college-application process against less-affluent students.

The board is also creating a program to try to persuade more low-income minority students to take Advanced Placement classes. About 3 in 10 black students with the academic background to take an A.P. math class do so, compared with 6 in 10 Asian-Americans.

Another program the College Board is creating will reach out online and mail packets to college-ready low-income students to encourage them to apply to more schools. Students who do so are more likely to attend a four-year college, data suggests.

Mr. Coleman, who was named College Board president last year, said that the new efforts were not an attempt to increase revenue for the group, which administers A.P. tests, the PSAT and the SAT. Low-income students typically pay $10 at most — most pay nothing — to take an A.P. test, and that revenue does not come close to covering the cost of the outreach programs, officials said. The overall effort, Mr. Coleman said, “is stretching the College Board’s budget, and we’re proud of that.”

Separately, the College Board on Thursday released SAT scores for the most recent year, highlighting another problem in American education: lack of college preparation.

More than half of the students who took the SAT in 2013 did not reach a benchmark indicating they would be prepared to succeed in college-level courses. The proportion who have reached that benchmark has flatlined in the past three years, with 43 percent hitting the threshold.

The information packets come in blue folders marked “Realize Your College Potential.” Each contains the waivers for application fees; information about admissions, financial aid and graduation rates; and advice about applying to college.

Mr. Coleman said the College Board would study the results and consider altering the program, like by creating slimmer packets that look less imposing and sending packets to sophomores or juniors based on PSAT scores.

Earlier contact could allow the College Board to reach students who take the ACT standardized test, which the group does not administer, rather than the SAT. Slightly more students take the ACT than the SAT.

The board’s efforts follow similar moves by colleges and states. Delaware announced last week that it had begun offering information packets and one-on-one advice aimed at getting more low-income students into top colleges. Many of the efforts stem in part from concern that the lack of economic diversity at top colleges is impeding mobility.

In recent decades, the economic returns on a college degree have risen sharply. The income gap between graduates and nongraduates is nearly the widest it has ever been. Similarly, the unemployment rate for graduates of four-year colleges between 25 and 34 was 3.9 percent in August, according to the Bureau of Labor Statistics. For nongraduates in that age group, it was 9.8 percent.

Motoko Rich contributed reportin