Ofsted has been warned that it cannot inspect the curriculum without taking school funding pressures into account.
The heads of two influential grassroots groups of school leaders have written to chief inspector Amanda Spielman calling for answers on how inspectors will take school funding into account.
Ofsted’s new inspection framework, which will be used from September, will place an increased emphasis on the school curriculum.
However the WorthLess? school funding group and Headteachers’ Roundtable have raised concerns that Ofsted will not consider a school's lack of funding as part of this judgement.
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In a joint letter, the head of WorthLess?, Jules White, and the chair of the Headteachers’ Roundtable, Stephen Tierney, ask: “If headteachers were unable to offer the curriculum breadth that may arise due to a lack of funding or a lack of specialist teachers in areas such as computer science, science, maths and English, would they be penalised during an inspection?”
The letter also asks if Ofsted believe there is a link between school funding and the quality of education a school can provide.
And it asks Ms Spielman if Ofsted will publish the per-pupil funding a school receives as part of the information presented in its inspection report.
Ofsted’s chief inspector told the Public Accounts Committee earlier this year that inspectors will carry out research into how schools spend their money.
Ms Spielman gave the pledge in response to a recommendation from the committee that she give her views on the causes of poor school performance, including the impact of funding pressures.
The letter from WorthLess? and Headteachers’ Roundtable asks if this research has “identified the severe and hugely variable financial constraints schools are operating under?”
It adds: “If it does, what will be the advice issued to inspectors and the mechanisms used to ensure schools facing financial constraints are fairly and accurately judged?”
The letter also questions the inclusion of government EBacc targets in the inspection framework and asks how will the inspectorate ensure schools with disproportionately high numbers of pupils with SEND or from disadvantaged backgrounds will be fairly and accurately judged?
The WorthLess? campaign led a march of headteachers on Downing Street last year to highlight the funding pressures schools are facing.
Mr White is concerned that despite its high profile the issue of school funding is not part of how Ofsted assesses a school.
He said: “There is no recognition in the framework about the impact of funding on a school’s curriculum or the quality of education provision a school can provide and yet if you speak to school leaders this is one of the biggest issues they face.”
An Ofsted spokesperson said: "We are pleased that these campaign groups welcome our new emphasis on the curriculum.
"From September, our focus on the quality of education will make it easier to recognise and reward schools doing the right thing in challenging circumstances.
"Our desk research on funding, published last October, found there is some limited evidence that reduced funding can have an impact on outcomes, but it is not conclusive.
"We are currently conducting a fuller study on school funding, which aims to qualitatively assess any wider impacts. We will publish this in due course."
Ms Spielman was criticised last year by the PAC over her answers on the impact of school funding pressures and for not speaking out more.
She had said that she would only comment on what the evidence shows and that Ofsted “haven't seen anything yet from school inspections that says that schools are unable to provide a good quality of education by reason of funding”.