The College Board disclosed yesterday that the problems resulting from the misscoring of its October SAT examination were larger than it had previously reported.
In a statement, the organization said it discovered last weekend that 27,000 of the 495,000 October tests had not been rechecked for errors. It said that after checking those exams and one other overlooked set, it had found that 400 more students than previously reported had received scores that were too low.
A board official added that the maximum error was 450 points, not 400.
This is the third time in two weeks that the board, which administers the exam, has acknowledged that its earlier assessment of the problems was wrong. In its statement, the board also outlined steps it planned to avoid mistakes.
The disclosures prompted fresh criticism that the board had not been as forthcoming as it should have been in disclosing the problems promptly and in detail.
"Everybody appears to be telling half-truths, and that erodes confidence in the College Board," said Bruce J. Poch, vice president and dean of admissions at Pomona College in Claremont, Calif. "It looks like they hired the people who used to do the books for Enron. My next question is what other surprise we're going to hear about next."
The board said two weeks ago that it had found scoring problems on the October SAT after two students requested in December that their tests be re-scored by hand. In the review, the board became aware of a more widespread problem.
It asked Pearson Educational Measurement, the large testing company that scores the exam, to rescore the October exams. As a result, the board found that 4,000 students had received understated scores and that 600 had overstated scores. The policy of the board is to change just scores that are too low. Pearson has said the errors resulted in part from too much moisture when it scanned the answer sheets to be graded by machine.
Last week, the board said 1,600 exams, separated for special processing because of security and other questions, had not been rescored. The board asked Pearson to rescore those tests. While awaiting that rescoring, the board asked Pearson to confirm again that all the October tests had been scored a second time. It turned out that they had not been.
Last weekend, the board said, Pearson informed board officials that 27,000 tests had not been "fully evaluated." Neither the board nor Pearson explained how or why those tests had been overlooked.
In rescoring the 27,000 tests this week, 375 were found to have scores lower than they should have been. The incidence of problems — 1.4 percent of the 27,000 — was significantly higher than in the first batch of problems, in which eight-tenths of 1 percent of the tests were misscored. An additional 18 misscored tests were found among the 1,600 separated from the rest of the October exams for special processing.
According to the board statement yesterday, the total number of students who received scores too low was 10 percent larger than it had reported before, approximately 4,400 rather than 4,000. The board said yesterday that 613 others had received scores higher than those they had earned on the three-part exam, which has a possible 2,400 points.
The vice president for public affairs at the board, Chiarra Coletti, said it would notify college admissions officers and high school guidance counselors last night through an "e-mail alert," and inform affected students today.
Pearson, one of the biggest players in the testing industry, has experienced other scoring problems. It started scoring the SAT last year.
In its statement yesterday, the board said Pearson would ensure that all answer sheets were "acclimatized before scanning" and would scan each answer sheet twice. Pearson will also improve its software to detect whether answer sheets have expanded because of humidity.
In addition, the board said Booz Allen Hamilton, the consultants, would conduct a "comprehensive review, with emphasis on the scanning process," over the next 90 days, and would recommend improvements.
Ms. Coletti said that she did not know how much the new procedures would cost, but that the test fee for the rest of this year would "certainly remain the same."
The board statement quoted Douglas Kubach, chief executive of Pearson Educational Measurement, as saying that the company regretted "the uncertainty and disruption these issues caused" and was "determined to take every possible necessary step to restore confidence in this process."
"Electronic scanning of answers is essential to giving the large number of students who take the SAT the speed and accuracy they require in this important test," he added.
A spokesman for Pearson, David Hakensen, said he could not provide more information on whether the new steps would mean higher prices.
Robert A. Schaeffer, public education director for FairTest, a group that criticizes heavy reliance on testing, said the new announcement reinforced "the need for an outside independent investigation to find out how many more problems have not been reported."
"The College Board and Pearson are clearly not competent to police themselves," Mr. Schaeffer said.