Sorting students by their ability has led to better educational outcomes, but Education Minister Ong Ye Kung acknowledged that streaming may come at the expense of students in the Normal streams losing confidence.
"The Ministry of Education (MOE) introduced streaming in 1980 to systematically customise learning for students of different profiles," he said on Monday in a written response to Mr Louis Ng (Nee Soon GRC), who asked in a parliamentary question whether his ministry has studied the effects of streaming on secondary school students' self-esteem and confidence.
"(Streaming) has very successfully lowered student attrition and improved educational outcomes," said Mr Ong, adding that studies by the National Institute of Education have shown that Normal (Academic) students, after spending some years in secondary school, had similar or higher levels of confidence in their studies compared to their Express stream peers.
"But there is also feedback from teachers that students in Normal streams may over time also lose confidence and the mindset of growth and development. The trade-off between customisation and stigmatisation is something we need to recognise."
To combat this trend and "blur the lines between education streams", he said, MOE has put in place measures such as subject-based banding, where students from the Normal streams can take subjects at a higher academic level, and the Polytechnic Foundation Programme, for students to join polytechnics without having to take the O levels.
"Our work in this area is ongoing," said Mr Ong, explaining that factors affecting self-esteem and confidence are complex and multi-faceted.
Mr Ng also asked whether there is a pathway for Normal (Technical) students who do well in the N(T)-level examination to take the O levels, beyond subject-based banding as an option.
In response, Mr Ong said that Secondary 4 N(T) students who perform well in the N(T)-level examination can first transfer to the Secondary 4 N(A) stream and take the N(A)-level examination. Thereafter, they can progress to Secondary 5 N(A) and take the O levels.
"This allows students to progressively bridge the gap between the academic demands of the N(T), N(A) and O-level curricula," he said.
Over the past five years, about 530 students each year have transferred from N(T) to N(A), he said, adding: "They are identified early, based on their secondary school performance."
Of all the N(T) students who move to the N(A) course, 10 to 20 of them go on to study in the Express track each year, he said.