A leading academic has accused Ofsted of doing “more harm than good” in a blistering attack on the inspectorate.

Frank Coffield, emeritus professor of education at the UCL Institute of Education, published his blunt conclusion in a blog posted today, following a review of research about the impact of Ofsted.

The blog, for the British Educational Research Association, says he has “carefully reviewed the evidence for the benefits of inspection as well as for any undesirable consequences”.

He adds: “The clear balance of the evidence made me conclude, however, that Ofsted currently does more harm than good. Its methods, although changed every few years during the 25 years of Ofsted’s existence, are still invalid, unreliable and unjust.”

The academic referred to a “detailed, empirical study” by the Education Policy Institute as having informed his point of view.

The report, released last year, concluded that Ofsted “may not be fully equitable to schools with challenging intakes” and that “notable proportions of ‘good’ and ‘outstanding’ schools are not down-graded”, even when their performance deteriorates substantially, according to Professor Coffield.

Professor Coffield added that the report said that the “most deprived schools are systematically more likely to be downgraded than the least disadvantaged”.

He said: “So much for the claim by the new chief inspector that Ofsted is ’providing fair, valid and reliable judgements’”.

Professor Coffield said: “The very schools that need most help are further harmed by inaccurate and biased Ofsted reports that make the recruitment and retention of teachers even more difficult. It also means that those heads chosen to become system leaders come from the most advantaged schools, so their advice to the poorest schools is likely to be wide of the mark.”

Ofsted ‘needs a complete overhaul’

A complete overhaul of Ofsted is needed, according to the academic, who has criticised Ofsted in the past.

He said: “Ofsted itself needs help. I recommend that its over-extended remit be drastically reduced, that it becomes genuinely independent of government and that it reintroduces a system of local and national inspectors. In this way inspectors would become once again respected colleagues, acting as the cross-pollinators of challenging ideas and novel practices in a joint search with teachers for improvement”.

This criticism of Ofsted comes on the same day that schools minister Nick Gibb described how the “scourge of the ‘Ofsted teaching style’” had dictated how pupils had been taught.

The regulator is currently under scrutiny by the National Audit Office (NAO) to see if it provides value for money to the taxpayer, and whether schools are being inspected efficiently and effectively.

Ofsted is also under pressure from opposition MPs, with shadow education secretary Angela Rayner recently branding it “not fit for purpose”.

Teachers need to unite in demanding a “more just and valid system of inspection by which to be judged”, according to Professor Coffield.

He said: “The organisation belongs to all of us who pay for it. So we have a right and a duty to call not just for some cosmetic tinkering but for a model that is based on our knowledge of how students, teachers and inspectors best learn.”

Ofsted was contacted for comment.

Want to keep up with the latest education news and opinion? Follow Tes on Twitter and Instagram, and like Tes on Facebook