New research has found that a school's Ofsted rating accounts for less than 1 per cent of observed differences in GCSE examination grades once pupils' prior attainment and socioeconomic background is weighted for.
Even when prior attainment and pupils' backgrounds are unweighted for, Ofsted ratings account for just 4.4 per cent of differences in GCSE grades.
Background: Teaching to the test hits GCSE resit grades
The study, led by the University of York, also found that Ofsted ratings had no bearing on pupils' wellbeing or enjoyment of school life, with pupils attending schools rated as "inadequate" by Ofsted reporting similar levels of happiness, bullying, future aspirations, satisfaction with school and ambition as those attending schools rated as "outstanding".
The data was based on 4,391 teenagers born between 1994 and 1996 who took part in the Twins Educational Development Study.
Out of these pupils, 27 per cent attended a school rated as "outstanding", 47 per cent attended a school rated as "good", 22 per cent attended a school rated as "requires improvement" and 4 per cent attended a school rated as "inadequate".
However, the research found that before pupils' socioeconomic background and prior attainment was weighted for, there was a difference of almost one GCSE grade between those attending "outstanding" and "inadequate" schools.
Pupils attending "inadequate" schools scored an average GCSE grade of a C, whereas those attending "outstanding" schools attained a mean grade of a B.
The report said that differences in GCSE achievement could be attributed to schools’ "selection of student intake, not to their added value".
"We also found that Ofsted-rated school quality was a weak predictor of student wellbeing and student engagement," it said.
"Overall, our findings suggest that individual student outcomes are largely independent of schools’ Ofsted rated quality."
Lead author of the study, Professor Sophie von Stumm, from the department of education at York, said: “We have found that the factors parents care about most when selecting a school – their child’s educational achievement and wellbeing – are negligibly predicted by Ofsted ratings.
“If Ofsted ratings don’t predict students’ achievement and wellbeing, we need to reconsider just how helpful they are in general. Ofsted inspections are extremely stressful for teachers – causing problems for recruitment and retention in the profession, and they are also very costly to the taxpayer, with the bill per visit coming in at around £7,000 per school on average.
“Parents often go to great lengths to secure a place at an ‘outstanding’ school for their children – either by moving house or commuting long distances. Our research suggests these investments don’t really achieve what they are aimed at – good grades and well-being for children.
"So parents should ask themselves: is an 'outstanding' school really worth spending an hour commuting each day rather than using the time to play or read?”
Professor Stumm added: "Due to high demand for places, schools rated ‘outstanding’ can be more selective about the pupils they enrol. They are also often situated in more affluent neighbourhoods with families of higher socioeconomic status.
"We know from previous research that children’s early years school performance and family background are two of the strongest predictors of their later educational achievement."
An Ofsted spokesperson said: "It’s not our ratings that impact on outcomes for pupils, it’s the quality of education that a school provides, which is down to the hard work of the staff.
"Our judgments recognise the schools that are changing lives – and we’ve found a close link between the progress pupils make at a school and its Ofsted rating.
"But above all, our inspection reports focus on what parents care most about: what it is like to be a child at a school, and what the school does well or could do better. And 8 out of 10 parents tell us they find our work useful."