After two delays during the morning, the scores were finally announced at 12.45pm - but only 89 per cent of them.

Many students remained in doubt as to whether their scores were correct and some parents planned to submit complaints to caretaker Prime Minister Thaksin Shinawatra today, asking him to end the use of the problematic tests.

At 8am yesterday, an hour before the latest deadline for the results to be revealed, the National Institute of Education Testing Service (NIETS) postponed the scores' announcement for the fourth time since April 1, the first scheduled date for the results. Caretaker Education Minister Chaturon Chaisang explained that a further 2,000 student answer sheets had been discovered late on Sunday night.

The results were set back to 10.30am, then to midday, before the announcement was finally made at 12.45pm.

Moreover, only 89 per cent of 349,000 students got their scores. The remaining students' scores were still being processed to match answer sheets with their real owners, acting director of NIETS Pratheep Chankong said.

A number of students whose test results were confirmed and announced yesterday voiced doubt about whether their results were correct. Some said their results in some subjects were significantly different from two previous announcements and asked to see their answer sheets in order to ensure all belonged to them.

"My O-Net result for mathematics dropped from a score of 52 to 14, and the social science result dropped from 77.5 to 32.5. While the A-Net result for mathematics, in contrast, increased from 57 to 71," Setthawach Phoolkasemsap, a student from Suan Kulap Wittayalai School, said.

"I intended to apply for the Mass Communications and Law Facul-ties at Chulalongkorn, which re-quired high O-Net scores. But the score dropped this time. I would like to double-check if that's correct. How can we trust this an-nouncement when the two previous ones had serious mistakes?" he said.

Siwadon Phinitkwamdee, a student at St Gabriel's School, said his English test score dropped from 20 to an incredibly low 4, and he believed he should have scored more.

Morrakot Satatikul, of Sai Panya School, and Nithi Charnpreechakul, of St Gabriel's, complained that they could not find their scores through the website.

At Naresuan University, Amornrat Klinjampasri from Phitsanulok said she had achieved an impossible score - 560 out of 100 for her Thai language test.

At Kasetsart University, 104 parents and students who came to check O-Net and A-Net scores decided to file complaints and asked to see students' answer sheets due to doubts over whether they were correct. However, due to technical problems, NIETS officials said they would be unable to do this until later.

Kamolphan Cheewaphansri, chairman of the Network of Parents and Youth for Education Reform, said members of the network would go to Government House today to submit a letter to the premier to stop O-Net and A-Net scores being used for university-entrance purposes.

"Many parents disagree on both tests but are reluctant to express that stance. Plus, the triple mistake in announcing the O-Net and A-Net scores in recent months have made us less confident in this new mechanism," she said.

NIETS' Sumontha Phromboon conceded mistakes in the announcements. She said these were due to both human error and problems with the system itself.

A special committee - chaired by an independent person - would be set up to look into human errors and determine appropriate punishments, she said.

However, caretaker Minister Chaturon insisted that the O-Net and A-Net tests would be implemented next year - but all mistakes would be corrected beforehand.

"This system is good in principle. It will solve what has been the weak point in the Thai education system in the past - the failure to equip students with critical and analytical thinking. However, we will have an open public hearing to adjust the admission system to make it more efficient," Chaturon said.

Meanwhile, a coalition of Medical Science faculties from nine leading universities said they would announce students selected for their faculties by Friday if the chaos from the O-Net and A-Net announcements ceases and all required scores arrived today.