Call it an edge. Call it a bonus. Whatever you call it, interest in Advanced Placement courses is growing and for good reason. It really confers an advantage.

A study recently produced by the College Board shows that students who take AP courses do better in college, and those who take both the courses and the exam do even better. The College Board also produces the AP tests - so there is a question about its own study - but that study fits into a pattern of other work and the experiences of local school and college staff.

A few years ago, the College Board requested an audit of AP courses, said Jeff Weiss, director of curriculum and instruction for the Racine Unified School District. They wanted copies of the syllabus for each course and other information, equal to a great deal of extra work for school staff if they wanted to retain accreditation.

"The first thought we had was, 'Is it worth it?' " Weiss said. Unified staff did their own research and decided it was. "And we've actually added a couple of courses since that time."

For Wisconsin as a whole, interest in AP work is also up. In 2004 state school districts administered 31,404 AP exams, and by 2008 that number had increased to 42,450. This is according to the Wisconsin Department of Public Instruction.

The reason for taking AP courses is its academic advantage.

"When students are in more rigorous classes they do better," Weiss said. College admissions workers agree as do some studies.

After they adjusted for ability, two researchers from the University of Missouri found that taking AP courses would be enough to boost the first-year grade point average of a college student from a B to half way between a B and a B-plus. College admissions people look at it this way: The more preparation students have, the better they are likely to do in college and the more likely they are to stay in college.

"That doesn't mean that that AP course is a plus in the admissions process, though," said Matthew Jensen, director of admissions at the University of Wisconsin-Parkside.

Admissions in the University of Wisconsin System is a holistic process in which academics play a big part but are considered with a student's community and extracurricular involvements and other markers of their character and skills.

Because the AP exams are taken in the spring of a student's senior year, in most cases that student has already applied to and been accepted at a college, Jensen said. But what admissions people say among themselves, he said, is that students who take AP courses come into college with a better understanding of what will be required of them and a greater breadth of knowledge about any given subject.

Even without the exam, however, AP work is still valued by admissions people because they know it is not only rigorous but standardized, said Tom Reason, associate director of admissions at the University of Wisconsin-Madison.

"We know that AP calculus means something whether it's from Madison High School or Dodgeville High School or Boise, Idaho," he said. "A course that's called Honors Math may be entirely a different thing from one high school to the next."

That brings up another point: grade inflation. Data from national college entrance exams show that grade averages and entrance exam scores continue to increase relative to students from previous years and generations, Reason said.

"Whether everybody's being more and more successful, or whether there are other social dynamics at play, I guess I'll leave that for others to debate."