Only 7% of the 1,964 maintained schools inspected during the first quarter of 2012 were judged to be outstanding overall, compared with 11% over the academic year 2010-11. Schools judged inadequate in 2012 outnumbered those that were outstanding as the proportion rose to 9% from 6% in 2010-11.

However, a comparison of schools that had had a previous section 5 inspection (all but 50 of those inspected in 2012) showed widespread changes in the performance of individual schools under the cover of an unchanged overall national performance. The judgements had stayed the same for 48% of schools, while 26% were given a higher overall judgement and 26% a lower one than before.

Brian Lightman, the general secretary of the Association of School and College Leaders (ASCL), said it was important for parents to recognise that schools have to keep improving in order to maintain the same grade. ‘A school rated good twice in a row will have had to improve in order to achieve that,’ he said.

The National Association of Head Teachers (NAHT) criticised the quality of the inspections, saying that ‘a dive into the detail reveals worrying inconsistencies’. Highlighting improvements in the failure rate during the three-month period, its general secretary, Russell Hobby, said these suggested ‘either an attempt by Ofsted to manage the impact, or an inspection workforce which is only now becoming competent at applying the framework correctly’.

He added: ‘We are now in our sixth inspection regime, with a seventh due this September – just nine months after the last. Every change introduces new mistakes as inadequately trained and ill-prepared inspectors make hasty judgements. Too few of the outsourced inspectors have real and recent experience of leading or teaching in the schools they inspect, resorting too often to a crude use of data rather than judgement.’

By David Gordon