The Higher Education Commission will need time to find the students who failed to provide complete identification information on more than 10,000 O-Net and A-Net answer sheets.

"We believe these answer sheets belong to a few more than 1,000 test-takers," secretary-general Pavich Thongroj said yesterday.

The re-scoring of answer sheets should be finished by Sunday but the results will not be released until the following Sunday because the commission planned to spend most of next week trying to identify the problematic answer sheets, he said.

"But if the identifying process could not be finished by April 30, we will announce the scores of most test-takers first," he said.

In that case, the commission will publish a list of students who need to contact it in a bid to determine which of the answer sheets are theirs.

Pavich was hopeful all the answer sheets would be matched to students before the deadline for submitting university applications.

This year is the first for O-Net (Ordinary National Educational Test) and A-Net (Advanced National Educational Test) results to be used as criteria for university admissions.

However, the scoring process has been marred by technical and human errors under the supervision of the National Institute of Education Testing Service. Earlier this month, NIETS twice voided the O-Net and A-Net scores it had announced.

The Higher Education Commission stepped in to help with reviewing the grading process.

Pavich said the failure by test-takers to fill in their identification card numbers correctly on the answer sheets was a reason why many got a zero. Other glitches include unscanned answer sheets and answer sheets with identical serial numbers.

"Some answer sheets share a serial number because at some test centres, there were not enough answer sheets for all the test-takers and the teachers decided to make copies," he said.

Sometimes two answer sheets were scanned as the same single answer sheet, causing confusion and wrong scores.

"It will take a lot of time to solve all the problems," he said.

NIETS acting director Prateep Chankong admitted that the body had denied access to the O-Net and A-Net scoring process by the programmers from Khon Kaen University who developed the marking software.

"We can't let the programmers in on the process because the answer sheets are confidential. Outsiders are not allowed to view them," Prateep said.

He insisted there were no problems with the scoring software.

"The software is good. All the problems are down to human error," he said.

Reports saying the NIETS had outsourced the answer-sheet scanning task to a private company were "groundless", he said.

"How could we have done that? We didn't even allow the software programmers to see the answer sheets."