Numbers taking and passing AP exams move up again

As Advanced Placement exams have expanded to a more diverse group of high school students, more failures and lower average results seemed almost inevitable. But recent high school graduates seem to be bucking the trend: For the first time on record, average scores, the percentage passing and top scores are all increasing.

In its annual report Wednesday on the AP Program, the College Board said nearly one-third of 2012 public high school graduates took AP tests, and nearly one in five received a passing score of 3 or higher on the five-point-scale exams offered in 34 subjects from calculus to history to studio art. Both figures are up substantially from a decade ago, when 18 percent of graduates took an exam and fewer than 12 percent earned a score of 3 or higher.

But more notably, the College Board said that for the first time since it began collecting data by class year in 2001, the mean exam score increased from the previous year, from 2.80 to 2.83. The percentage of all exams that earned at least a 3 also rose for the first time, and the 14.2 percent earning a top score of 5 was...