A key Government drive to improve the quality of teaching in Welsh schools is at risk of failure without continued investment and better implementation by heads, the academic behind the policy has warned.
So-called "professional learning communities" (PLCs) are in danger of becoming "just another initiative" that will have a limited impact on standards, according to Professor Alma Harris, an adviser to the Welsh Government.
Professor Harris, who is pro-director of London University's Institute of Education, said that the communities can make a positive difference to learning and has urged teachers to "grasp the opportunity with both hands".
At its most basic, the initiative aims to bring together teachers and other education professionals to share best practice and address the specific needs of learners. It is a key part of the Government's attainment-raising school effectiveness framework (SEF) policy, and so far around 1,900 schools and all 22 local authorities have gone through the training programme.
Heads are expected to set up PLCs and keep them running, but leadership should be shared among members. As well as improving school standards, the Government is keen to promote them as a powerful staff-development tool.
But critics have attacked the idea as a "waste of time" and lacking content. Even supporters are concerned that there is too much variability in their quality and a widespread lack of awareness about their importance.
Writing in today's TES Cymru, Professor Harris says there is excellent classroom practice in Wales that must be shared if school standards are to improve. Learning communities engage teachers in this process and put them "in the driving seat of change", she says.
"However, unless PLCs are properly established, supported, challenged and sustained, their impact will be diminished. To ensure that PLCs are not relegated to the status of yet another initiative it is imperative that there is further investment in their sustainability.
"The next challenge is to go deeper with the PLC work, to ensure that each school is using data to inform the enquiry process related to the education minister's three priorities - literacy, numeracy and closing the poverty and achievement gap."
Professor Harris said forcing teachers to work together and coercing classroom change would be counter-productive, and the policy must instead "win hearts and minds".
"We have all the expertise we need in the Welsh system to improve our system - we just need to make deeper and better connections. Professional learning communities are one way to make those deep connections, but they cannot be, and were never intended to be, a panacea for all the shortcomings in the system," she said.
But Terry Mackie, director of educational consultancy Empathi Cymru and a former head of school improvement for Newport Council, said PLCs are a "failing initiative".
"The idea was a non-starter from the beginning because it is completely lacking in content," he said. "Given the amount of time and attention lavished on PLCs, why haven't they taken off yet?
"Many schools don't know what they are about and those that do can't see anything new in them. This is a half-idea that has been built up into a national priority."
Dr Philip Dixon, director of the Association of Teachers and Lecturers Cymru, said teachers who experience PLCs are generally positive about their value, but admitted that other teachers still have "little or no idea" of what they really are.
Dr Dixon agreed with Professor Harris that PLCs need continued investment, and said local authorities should play a bigger role in promoting them. "This is a flagship initiative that must not become stifled by local authority inertia," he said.
A Welsh Government spokesman said it does not know how many PLCs have been set up, but the information should be held locally.
"The education minister is due to receive further advice on the next stage of the development of PLCs in Wales within the next month, and further information on the long-term plans for this policy area will be available before the end of this academic year."