Thousands of high school students across the state received a letter from UC President Janet Napolitano this week as part of a new effort to encourage high-achieving, low-income students to apply to the university.

The letters, which were sent to about 5,000 students, are part of a new partnership between the university and the College Board, the nonprofit organization that administers the PSAT, SAT and Advanced Placement exams.

The letters were targeted toward ninth- to 11th-grade students whose PSAT scores demonstrated their potential to succeed in advanced academic work, according to a statement from the UC Office of the President.

“The letter itself is really just the affirmation of their good work and to encourage them to prepare for college,” said Stephen Handel, UC associate vice president of undergraduate admissions.

Napolitano wrote to the students and urged them to enroll in college-level AP classes that can bolster a student’s college application. She also mentioned the university’s Blue and Gold Opportunity Plan, a program that covers systemwide tuition and fees for students whose families make less than $80,000 annually and qualify for financial aid.

“The College Board’s goal is to support college readiness and success for more students,” said Katherine Levin, associate director of communications for the College Board. “Our work with the University of California is guided by these goals.”

C. Judson King, director for the campus’ Center for Studies on Higher Education, said taking AP classes and making families aware of financial aid programs can help encourage prospective students to apply.

“Somebody who takes an an AP course is more likely to have a desire to go to a college or university because it awakens a higher level of learning within them,” King said.

Even just receiving a letter from the UC president can go a long way in getting students to apply to the university, King said.

The number of low-income students applying to the university has remained relatively stable in recent years, according to UC data.

For fall 2014, 36.7 percent of Californians applying for freshman admission to UC Berkeley came from a low-income family. UC Berkeley tied with UC Davis for the lowest percentage of freshman applicants coming from a low-income family. UC Merced had the highest percentage.

The university has looked to alternate methods of boosting diversity across its campuses since Proposition 209 was passed in 1996, prohibiting the use of race, gender or ethnicity in UC admissions decisions. One of its strategies has been investing in outreach programs for low-income communities.

“We’re looking for every way legally permissible to encourage diversity and increase diversity at UC,” said UC spokesperson Brooke Converse. “That’s one of UC’s longstanding goals, and nothing has changed.”