Amy Brecount White, a former Advanced Placement English teacher, has written for Arlington Magazine one of the best pieces ever on high school academic pressure. Her most chilling discovery is that many students are making bad decisions because of a widespread misunderstanding of the college admissions system.

“There are those competitive students and their competitive parents who can’t help wondering whether that one extra AP class — and the sacrifice that comes with it — could mean the difference between acceptance to a first-choice school versus the consolation prize of a back-up ‘safety’ school,” White reports in the article.

Students and parents who think that way are sadly misinformed. Among the many myths about how to get into your first-choice school, this one is particularly harmful because it leads students to waste time and become unnecessarily stressed.

I have covered college admissions for The Washington Post for more than two decades and published a book on that subject, “Harvard Schmarvard,” in 2003. I have interviewed scores of college admissions officers and read the briefing materials of hundreds of colleges. Not one has ever said that adding an Advanced Placement class can make or break one’s chances of getting in.

Selective colleges want to see applicants take the most challenging courses at their high schools. In most cases, particularly in the Washington region, that means AP, International Baccalaureate or the Advanced International Certificate of Education. Selective colleges also like to see three to five AP courses, with good scores on the tests to show that the student is ready for college work. That can be accomplished by taking one AP course sophomore year, one or two in the junior year and one or two in the senior year — not an overwhelming burden for any student with a shot at a selective college.

Taking six, seven, eight or 20 AP courses will almost never make you more attractive to those colleges that reject more students than they accept. Your chances with them depend on your SAT or ACT scores, the depth of your extracurricular activities, the warmth of your teacher recommendations and your grade-point average compared with other students at your school applying to the same college.

White quotes some experts and local educators who blame me and my annual America’s Most Challenging High Schools list for putting pressure on students to take AP, IB or AICE classes. Such pressure existed for families with selective college ambitions long before I created the list. I measure AP test participation, not AP test scores. The list was designed to encourage high schools to get students heading for non-selective colleges to take AP, IB or AICE courses also. They need that kind of academic challenge — one or two AP courses and exams — to be ready for any college. Most high schools don’t encourage average students to take such courses — and in some cases the schools bar them from doing so.

White provides much detail on how Arlington high schools have pioneered ways to get low-income and minority students into AP and IB courses and succeed. They get extra support with special clubs and classes. “I feel like I’m around smarter people now, so the classes go more smoothly. . . . I like being challenged,” an African American student at Wakefield told White in her article.

White also exposes the effects of peer pressure, including the experience by a Yorktown High School student who took a fourth AP class her junior year because her friends were taking it. When she found herself taking sick days to catch up with her work, she wisely dropped the class. A student who can’t handle more than one AP class a year shouldn’t take more than that. Disturbingly, there are many students throughout the country — one study put the number last year at 300,000 — who can handle a few AP classes, but aren’t taking any.