More Florida students than ever are taking tough college-level classes in high school.

Over the past decade, Florida has invested nearly $650 million in Advanced Placement programs and incentives like teacher bonuses. But with four in 10 students passing the AP exam in 2012, is it worth it?

It depends on how you measure the results:

•  Enrollment is way up. Over the past decade, the number of students taking AP exams has nearly tripled.

•  More minority students are taking the classes. Broward and Miami-Dade have gotten top honors in the country for Hispanic and black students’ participation and performance on AP.

•  Passing rates have slipped statewide. Statewide, 45 percent of test-takers pass the AP exam. At some South Florida schools, the passing rates are 10 percent or less.

•  The classes have become crowded. In 2011, the state Legislature exempted AP from class size rules.

In 2012, nearly a third of all 10th- through 12th-graders took an AP test, according to Department of Education records. The first big increase in AP enrollment came after the state partnered with the College Board, under former Gov. Jeb Bush. The number of AP test-takers jumped by 25,000 students, or nearly 20 percent, in 2010 when state administrators included AP in the school grade formula for high schools.

Last school year, the state spent more than $70 million in incentives for AP classes. That’s about $500 for every passing score, slightly less than the cost — about $600 — for three credit hours at Florida International University.

Florida and the College Board have a close partnership, started under Bush. The state pays exam fees for the College Board tests. Teachers get bonuses if students pass. The state’s contract with the College Board, for nearly $4 million in 2011 and $1.6 million through September 2012, includes workshops for counselors, administrator scholarships to a summer AP program, course audits and other training.

OPEN ACCESS

The college-level program used to be known as a VIP program for elite students. Now it’s more about open access.

Consider Miami Jackson Senior High, a long-struggling school that earned its first A from the state in 2011.

Julian Cazañas, the former principal who now works in adult education, said most of the AP students at Miami Jackson will pass the high school class, but not the AP exam, which is rigorous and scored by outside graders.

While Miami Jackson students taking AP exams grew over the past decade, from 83 to 135 students, 14 percent of them passed their AP exam in 2012.

“Participation is way up, but performance isn’t necessarily there. The game is too new. The exposure is too new. I think you’ll get a balance after students get two or three years of exposure,” Cazañas said.

He compared it to a student going to an opera for the first time and walking out with nothing to say. “Maybe after two or three times of seeing that opera, maybe that child can say something.”

Other educators and students agree AP has benefits beyond getting college credit for free. The curriculum exposes them to more information. Students generally have to write more and under tight deadlines. The format is supposed to spur critical thinking, independent study and confidence.

BriAna Hartfield said her AP environmental science course was one of the toughest science classes at Miami Jackson. “You’re more on your own. You take the textbook home, and you have to read. If you don’t, you’re lost,” she said. She passed the exam with a 3 and now attends the University of Miami.