The high school class of 2006 recorded the sharpest drop in SAT scores in 31 years, a decline that the exam’s owner, the College Board, said was partly due to some students taking the newly lengthened test only once instead of twice.

Fatigue wasn’t to blame, the College Board insisted, even though this year’s class was the first to take a new version of the exam, which added an essay. It now takes an average of three hours, 45 minutes to complete the test, not counting breaks, up from three hours previously.

In Kansas, the relatively few students taking the SAT scored better than the national average, including the essay portion. But the average critical reading score declined compared with 2005.

The results come several months after numerous colleges reported surprisingly low SAT scores for this year’s incoming college freshmen. The nonprofit College Board, which had said scores would be down this year, released figures Tuesday showing that combined critical reading and math skills fell seven points on average to 1021.

The average critical reading score fell from 508 to 503, while math dropped from 520 to 518. On the new SAT writing section, the class scored 497 on average, with girls scoring 11 points higher than boys.

The average scores for Kansas were 566 for writing, 582 for critical reading and 590 for math, up two points from 2005. A perfect store is 800.

The College Board noted that the drop in math scores amounted to one-fifth of one test question and the reading to one-half of one question. But with about 1.5 million test-takers, such drops are significant, and this was the biggest year-to-year decline since the class of 1975.

The results come two weeks after it was announced the class of 2006 had posted the biggest score increase in 20 years on the rival ACT exam. The ACT, which also is accepted by almost all colleges that require standardized tests, is generally more focused on material covered in high school classes than the SAT, which is more of a measure of general ability.

The ACT is far more popular in Kansas than the SAT. This year, only about 2,500 students in the state took the SAT, compared with 23,000 for the ACT.

Nationally, the initial indication that SAT scores were down prompted speculation that students may have become tired near the end of the exam. But in announcing the scores, the College Board said an analysis of 700,000 critical reading and math exams taken in the spring and fall of 2005 showed students were performing about the same early and late in the exam.

Instead, the College Board explained the drop by saying fewer students were taking the exam a second time, which typically boosts scores 30 points.

On the SAT, boys’ scores fell eight points from 513 to 505 in critical reading and from 538 to 536 in math. Girls’ scores fell from 505 to 502 in reading and from 504 to 502 in math.