I'm Doug Johnson with the VOA Special English Education Report.

The Advanced Placement program is fifty years old. As we reported last week, it was created to let high school students do college-level work. They can earn college credits if they do well on an exam.

In the United States, one-third of students who graduate from high school take at least one Advanced Placement course. Choices differ from school to school. Yet schools in poorer areas might offer few A.P. courses or none at all.

The program has many supporters. They point to studies that show that students with A.P. experience are better prepared for college. In fact, some arrive with enough credits to start at the second-year level. That saves money.

But the program also has critics. Some students and educators say A.P. classes often try to teach too much, so the learning is not very deep. And critics argue that classes can seem taught too much to the exam. Students and teachers might not have a lot of time to explore other areas.

Another issue has to do with the increasing competition for college. Some education experts say the fears of parents are helping to fuel the growth of A.P. classes. But a study by two economics professors suggests that the program might be expanding too fast to guarantee quality.

Kristin Klopfenstein and Kathleen Thomas compared the performance of students in Texas. They say A.P. students were no more likely than non-A.P. students to have higher grade point averages after their first semester at college. They also found that students with A.P. experience were generally no more likely than others to return for a second year of college.

Another researcher, Philip Sadler, presented a study last week at a meeting of the American Association for the Advancement of Science. This study involved students who got high marks on an A.P. science exam but still took a beginning-level science class in college. Mister Sadler says they did well, but not as well as many people might have expected.

The College Board, which administers the A.P. program, says the study was too small to mean much. It says other research shows that students who do well on Advanced Placement exams are likely to be more successful in college.

This VOA Special English Education Report was written by Nancy Steinbach. Read and listen to our reports at voaspecialenglish.com. I'm Doug Johnson.