College Board officials said yesterday that more college-bound students have A averages than a decade ago -- but they score lower on their SAT exams. The situation is sufficiently troubling to executives at the College Board -- the nonprofit organization that sponsors what was formerly called the Scholastic Aptitude Test -- that the board is commissioning a study by Rand Corporation researchers. Officials blame the trend on grade inflation by high school teachers.

• The College Board said that test takers with A averages grew from 28 percent of the total to 38 percent in the last 10 years -- but their scores fell an average of 12 points on the verbal portion of the SAT and three points on math.

• Suburban students are improving their scores, while urban and rural students are falling farther behind -- with a 30-point gap separating urban and suburban students.

• Also, SAT scores of children of parents with less education are falling farther below the national average.

Overall scores for the 1.2 million students who took the SAT last spring remained about the same as last year, with the average score on the verbal portion unchanged at 505 and the math portion up a point at 512 -- which some researchers attributed to students being able to bring along their calculators to the test.

College Board president Donald M. Stewart said that grade inflation "could be the result of the increased emphasis on accountability by teachers." Bob Chase, president of the National Education Association, said it "may result from pressures from both parents and the schools." And others say it may in part be due to the increased number of students taking Advanced Placement courses for college credit -- since they may receive weighted grades that are higher than an A.