The developer of the software being blamed for the examination scoring fiasco says there is nothing wrong with it and that clumsy employees at the National Institute of Education Testing Service are responsible for all the errors.

The software was developed by Bandit Thinkhamrop, an academic at Khon Kean University, and used by the testing service to tabulate Ordinary National Educational Test (O-Net) and Advanced National Educational Test A-Net) scores.

The testing service has announced and then voided the scores twice, leaving anxious, university-bound students and their parents up in arms.

Bandit insisted that since he had been appointed to develop a system for the O-Net and A-Net scores last October he and his team had designed it to effectively handle both multiple-choice and open-end examination questions.

His staff had overseen the process by which answer sheets were scanned and the information verified, but two days before the actual scores were tabulated his team was sent out of the premises to prevent possible cheating, Bandit said.

Employees of the testing service told his staff to leave "as soon as the answer-sheet scanning started", he said.

His staff then trained the testing service employees how to use the software.

But the process was quite complex and there was a massive number of answer sheets, he said.

Bandit blamed the subsequent problems on unskilled staff who failed to properly use the programme and verify results.

It took five years to develop his software which is based on Thai software called Optical Recognition, he said. It has been used in more than 10 research projects in order to reduce human error in the process of typing raw information.

Critics, however, have said his software has acute problems, especially when dealing with English and Thai papers.

Chulalongkorn University's Faculty of Engineering has subsequently been commissioned to design replacement software, which will release new scores for 400,000 potential university students on April 30.

"Now, people blame the software and its developers.

"In fact, the software itself has no problem, but it was the users who messed up," Bandit said.

He said he had sent an open letter to Khon Kaen University's rector to explain the incident because he feared the situation might damage the university's reputation.