Every school in Wales has been banded using colour-coding in the new National Categorisation System and the results published online.
Education minister Huw Lewis says the process provides valuable information and ensures support is targeted. But teaching unions have said that it simply stigmatises schools.
All schools have been allocated one of four colours with green representing the top performing schools, yellow for good schools, amber for schools in need of improvement, and red for schools in need of the most improvement.
Out of 1,332 primary schools assessed, 206 have been put in the green support category and 58 have been put in the red support category.
Out of 211 secondary schools, 30 have been put in the green support category and 23 are in the red support category.
Chris Howard, acting director of NAHT Cymru, said the categorisation system “traps some schools in long-term intervention even when they are doing very well in their own context”.
The categorisation was published just 48 hours after chief inspector of Estyn, Ann Keane, published her final annual report. Ms Keane, who is to stand down in the spring, said overall there is “general improvement in literacy and numeracy” but “this is happening at a relatively modest pace”.
Standards in secondary schools have improved when compared with “a relatively weak performance” the previous year.
The report found that the proportion of secondary schools with excellent or good standards rose to over half in 2013/14, compared with well under a half in the previous 12 months.
And in 2013/14 no secondary school required special measures after a core inspection when, by contrast, six schools required special measures in the previous academic year.
However, the report concluded: “There remains in nearly all secondary schools, even in the best, a general need to improve standards in mathematics and numeracy, in provision for more able and talented pupils and in pupils’ performance at Level 2 including English or Welsh and mathematics.”
Dr Philip Dixon, director of ATL Cymru, called for less scrutiny and more support. He said: “It is vitally important to heed the chief inspector’s call for a correction of the ‘imbalance’ between mechanisms aimed at increasing accountability and those which build capacity. The focus now needs to shift from measurement to nourishment.
“Finally, one piece of the educational jigsaw still remains missing. While schools, colleges, and local authorities have been subject to robust investigation, the Department for Education and Skills has escaped such scrutiny. It too would benefit from the rigorous inspection and forensic analysis that Estyn brings.”