The lecture, on primary education, was attended by 110 principals and teachers.

Professor Lo, director of the institute's Centre for Learning-study and School Partnership, said such collaboration improved both students' performance and teachers' understanding of factors marring weaker students from learning.

'In many cases, teachers started to think about questions that they might have never thought of. Does what is in the textbooks mean the whole content of teaching?

'How do teachers design special lesson plans for students of different abilities? Learning-study often inspires such questions,' she said.

The centre has introduced learning-study to 42 primary schools, 72 secondary schools and six special needs schools in a three-year project since 2005.

Education researchers visit the schools, observe how a lesson is taught and identify its critical features - often noticing difficulties students have in understanding a topic.

The researchers and teachers then get together regularly to form improvement plans and evaluate classes again after implementation.

It takes about three months for a learning-study to be completed.

Professor Lo cited the case of a primary schoolchild whose storytelling skills improved significantly after teachers adopted a new teaching strategy developed during learning-study.

The pupil had previously been able to tell only a small part of a story he was asked to recall, spoke in broken sentences and mixed up one character with another.

Teachers and researchers sat down together and found that the method used - asking students to memorise the story and then recall it - was not effective on pupils with a poor memory.

They then worked out a new lesson plan requiring teachers to explain to weaker pupils the detailed steps for memorising a story.

The plan involved pupils noting the key elements of a story - such as characters, time, places and events - and studying how the elements developed in the different stages of the story.

After adopting the new method, the weaker pupil could tell almost the whole story and speak with a degree of fluency comparable to a high-scoring pupil in his class.

'Individual difference is often a headache for many teachers. More capable students - because of their learning abilities - would become even more capable, while comparatively weaker students would become weaker. Their gap widens as time goes by,' Professor Lo said.

'But if teachers can find suitable ways to teach, many topics can be taught to different students, and even low-achievers can eventually do well.'

Professor Lo said a survey of 1,500 teachers who had participated in learning-study found that more than 80 per cent agreed it could help them identify the critical aspects of learning, make better use of assessments and improve teaching quality.

'Certainly, we cannot expect that a single learning-study can change the performance of every student. Teachers need to refine their teaching and learning approach frequently,' she said.

'Learning-study is only a start for teachers to think more about their teaching, rather than an end.'