December marks the beginning of my 24th year writing about the Advanced Placement program in high schools. I haven't had much competition.

Relatively few people know or care about these college-level courses, sponsored by the College Board, that energize high schools and prepare students for higher education.

Seventeen years passed before I saw the first major effort to ascertain the impact of AP courses and test-taking on average high school students. That 1999 report, "Answers in the Tool Box," by U.S. Education Department senior researcher and Montgomery County resident Clifford Adelman, was not really about Advanced Placement. But Adelman included AP among the intense academic experiences that his data indicated gave high school students a better chance of graduating from college.

So after more than two decades of underwhelming scholarly interest in this topic, I am delighted to report a surge of serious AP research, with four new studies in the past year and a fine piece by Andrew Mollison in the latest issue of the quarterly Education Next summing them up [see]. One study in particular merits attention: "The Relationship Between Advanced Placement and College Graduation," by Chrys Dougherty, Lynn Mellor and Shuling Jian of the National Center for Educational Accountability.

I think this issue is important to Fairfax County readers because AP and the much smaller but even more demanding International Baccalaureate program are becoming the standard by which education in the county is structured and measured. School superintendents and school boards have created in Fairfax County an AP and IB system that is the largest in the country and more open to average students willing to work hard than in any other school system I know.

Almost all the new studies show that students who get a good score on an AP test in high school do better in college than those who get a bad score or don't take AP. But I am also interested in how those students with bad scores did in college compared with students who did not take AP. Many AP teachers have shown me examples of students who did poorly on the exam but did well in college -- in part, they think, because struggling with AP gave them a useful dose of thick-reading-list-and-long-final-exam trauma.

Dougherty and Mellor, the principal authors of the center's study, considered an alternative explanation for that result that has also been suggested to me by several readers. Maybe the students who took and flunked an AP exam were statistically more likely to graduate from college than those who never took an AP exam, not because taking AP helped them but because they were more motivated, more persistent, more likely to keep going even if they flunked an AP test or struggled in their freshman year at college.

Dougherty and Mellor found no way to measure how motivated those who flunked AP tests were in comparison with those who didn't take the tests or the courses. But they were able to compare those who took and flunked the AP test with students who did not take the AP test and were of similar economic status and academic achievement, and who attended high schools with similar average incomes and academic achievement.

The paper is full of cautious statements, since Dougherty sometimes puts great weight on a relatively small sample of students. But his results indicate, in most cases, that students who take and fail an AP test are not much more likely to graduate from college than similar students who do not take an AP test.

Among students not considered low-income, there was no advantage for those who took and failed an AP test, according to the Dougherty-Mellor study. But low-income students who did so were 5 percent more likely to graduate from college in five years than similar students who did not take an AP test. Low-income white students were 3 percent more likely and Hispanic students 1 percent more likely.

Black students who took and failed an AP test in high school had a much larger advantage over blacks who didn't take an AP test -- a graduation rate 18 percent higher. But the number of black students in the study was so small that Dougherty warned against making much of that result.

Dougherty and Mellor say they have not settled the issue. "We have not shown that there is no advantage to taking AP courses for students who struggle with the material," they said. Dougherty emphasized to me that motivation is a powerful force, hard to measure with his numbers, and that high schools at the very least should not discourage students who want to work hard in a college-level course such as AP or IB.

But because there is now so much AP and IB course- and test-taking in Fairfax County, I am wondering what parents, students and teachers think are the advantages and disadvantages of these programs. My view is that average students have little or no chance of getting good grades on AP tests, and thus being prepared for college, unless their high schools let them take AP courses. Similarly, there appear to be no indications that taking and flunking an AP test hurts.

But what have you experienced in this regard? You live in a county that is one of the leaders of the AP revolution. How is it working for you?

Please send your questions, along with your name, e-mail or postal address and telephone number to Extra Credit, The Washington Post, 526 King St., Suite 515, Alexandria, Va. 22314. Or e-mail