NAHT conference to hear Wales heads' school banding opposition
Head teachers are to restate their opposition to the secondary schools banding system in Wales at a union conference this weekend.
The National Association of Head Teachers (NAHT Cymru) says publishing a single grade to show school performance is "unhelpful" to parents.
It wants a system to reflect different aspects of a school's performance.
The Welsh government said its approach was sophisticated, aimed at improvement and there would be no rethink.
From last year, secondary schools in Wales have been ranked into one of five bands based on GCSE exam performance and pupil attendance.
In March, those lowest-ranked secondary schools were promised more funding to improve standards.
The Welsh government said it had set aside £10,000 for every school in the bottom two bands of the performance-grading system.
The introduction of a similar system in primary schools has been delayed until 2014.
The NAHT union begins its annual conference in Harrogate on Friday, and NAHT Cymru will put a motion forward restating its opposition to the banding, and offering a "report card" system instead.
If it is supported the union will take its idea to the Welsh government.
Anna Brychan, the director of NAHT Cymru, said the union was happy to talk about a system of accountability which looks at what a school achieves, but said the banding was a "blunt instrument".
"(It) does not give the necessary precision for us to be sure that scant public resources are being targeted at the parts of the school system where they will have the most positive impact," she said.
Instead the union wants what it calls a "report card" for schools, where a series of grades would be given on different aspects of a school's performance.
"This would give parents, teachers and local authorities a far clearer idea of the strengths and weaknesses of a school, and allow the intelligent targeting of scant resources," Ms Brychan said.
She said the current system had left many parents "frankly puzzled" when school inspectors Estyn judged work to be "excellent" yet some schools were then given a low banding rating.
In a statement a spokesperson for the Welsh government said that education minister Leighton Andrews had made it clear there would not be a rethink of the school banding system.
"Banding was a manifesto commitment of this government and it is being implemented," he said.
"We believe that through the banding process we have introduced a constructive evaluation process which leads to targeted support to improve performance in our schools."
This approach was at the heart of the agenda to improve schools, the statement added.
"We have always said that banding is not about labelling, naming or shaming, or creating a crude league table.
"It is about putting schools into groups to identify which need our support and which we can learn from."
The spokesman added the Welsh government's approach was "far more sophisticated approach" than used in other parts of the UK.