Ofsted’s own head of research has admitted that it is impossible to determine conclusively how reliable school inspections are.

Daniel Muijs, who was appointed to the role at the start of this year, said: “No system is 100 per cent reliable: that’s never possible. And, always, any inspection involves human judgement.”

Questioned as to whether the inspection system would stand up to research, he pointed to two studies investigating the reliability of inspections. One, conducted in 1998, “came up pretty positively”, Professor Muijs said. But he added: “That’s now old evidence.”

A second study, published last year, looked at the reliability of Ofsted’s short inspections. This involved sending two inspectors to visit 24 primary schools, and concluded that short inspections were 92 per cent reliable.

‘Many different forms of inspection’

In the past, Robert Coe, education professor and director of the Centre for Evaluation and Monitoring at Durham University, has criticised Ofsted’s inspection process, saying that it was neither research-based nor evidence-based.

But he concluded that a finding that 8 per cent of inspections were unreliable was no cause for concern.

However, Professor Muijs admitted that one should avoid drawing too many conclusions from a single small-scale study.

“Of course, one study has always got its limitations,” he said. “There are many different strands of inspection, many different forms of inspection.

“And there are limitations to how large-scale you can go with those kinds of studies, because, of course, we do not want to overburden schools and constantly be sending multiple inspectors into schools.”

Professor Muijs made his comments as Tes publishes a wide-ranging investigation into the collapse of the school-accountability system.

This is an edited article from the 16 March edition of Tes. Subscribers can read a full profile of Daniel Muijs here, and the investigation into the failures of the accountability system here.  To subscribe, click here. This week’s Tes magazine is available in all good newsagents. To download the digital edition, Android users can click here and iOS users can click here

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