THIS year's inspection report on Pen-y-dre school in Merthyr Tydfil could serve as an advertisement for the "high-reliability" school improvement programme.
"The quality of teaching has improved overall since the last inspection (in 1996)", says Estyn, the Welsh inspectorate. "It is at least satisfactory in 97 per cent of classes and good or better in 69 per cent. The consistency of the good teaching is a strength and displays many features of good practice, which have been shared."
The programme, which is being trialled in 12 Welsh secondaries, is based on the theory that schools can be as reliable as air traffic control.
Consistency of approach - achieved by teachers learning good practice from each other - lies at the heart of the scheme, in which the 1,000-pupil comprehensive has been involved since 1996.
When John Williams came to Pen-y-dre as head in 1993, he found the staff agreed on the need for concerted action to reduce pupils' truancy and raise attainment. With a fair amount of local publicity, his first response was to go for a few eye-catching "quick fixes". He set a target - to double the proportion of pupils achieving five Cs or better at GCSE (it shot up from 11 per cent in 1994 to 32 per cent in 1995 and is now about 40 per cent - five percentage points above the Merthyr Tydfil average but still lower than the Welsh average of 50 per cent).
He introduced a review of classroom practice and a new behaviour code based on rewards. He tidied up the site, building a new entrance hall.
However, Mr Williams came to realise that the school was "flying by the seat of our collective pants" with these one-off initiatives and that targets needed to be rooted in a philosophy that could sustain continuous improvement.
A chance encounter in a pub with David Reynolds, the Exeter University professor overseeing the UK's "high reliability" pilots, led to Pen-y-dre becoming one of the first four Welsh schools to take part.
Mr Williams stresses the advantages of belonging to a "sustaining network" giving access to the latest research on the most effective methods. And he underlines the emphasis on using data to help staff improve their practice themselves.
"The classroom audits we conducted at the beginning had too much of the de haut en bas about them," he says. "Peer lesson observation and the development of our self-review process changed that.
"High reliability has just become part of the way we work. That's the strength of it."