The Ordinary National Educational Test (O-Net) may be limited to four core subjects -- mathematics, science, Thai and English, the permanent secretary for education, Chaipreuk Sereerak, says.
Mr Chaipreuk said the Education Ministry plans to discuss with the National Institute of Educational Testing Services (Niets) the possibility of reducing the number of subjects included in national tests for students in Prathom 6 (Grade 6), Mathayom 3 (Grade 9), and Mathayom 6 from the current five to four, leaving out social science.
Under the plan, social science may eventually to be excluded from the O-Net tests because the subject's content varies depending on the local context of different areas. It would not be practical or fair to incorporate it in the central test where students take the same test regardless of where they came from.
"The main idea is to get a more accurate assessment of a student's basic knowledge and skills as we think it's really hard to measure a student's social science knowledge in a manner that best reflects the context of each location," he said.
To assess a student's social science knowledge, schools must set their own examination questions and set the test themselves, Mr Chaipreuk said.
Social science would be tested separately and the score could count toward the O-Net assessment, he said.
The proposed change to the O-Net test will also be discussed with the Council of University Presidents of Thailand by the end of this year.
Mr Chaipreuk said the proposed change could be implemented quickly. This could be done through the exercise of special powers under the military regime. Normally, such a change requires at least three years' advance notice to allow educational institutes and students time to adjust.
He said a test covering fewer subjects could reduce stress for students and parents and help them save on after-class tutorial costs.
Back in 2015, the Niets reduced the number of subjects tested in O-Net exams from eight to five.
The three subjects dropped were; health and physical education; arts; and academic professions and technology.