Imposing a flawed new inspection framework could damage the relationship between schools and Ofsted, a heads' leader will warn today.
Paul Whitman, general secretary of the NAHT headteachers' union, will speak at a heads' conference.
He is expected to say that "now that school leaders have had the chance to look at the detail in the new framework, they are worried by it".
“A system that has promoted fear, driven perverse activity and increased workload over many years has left trust in the inspectorate at a low base,” he will say, according to pre-released remarks.
“It will take time to rebuild that, but at least the journey has started. One thing that would accelerate this process is a new inspection framework that commands broad support from the profession.”
Ofsted will change the way it inspects schools from September, focusing more on the curriculum and penalising so-called ‘exam-factory’ schools.
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The inspectorate plans to replace the judgements for outcomes, and for teaching, learning and assessment, with a broader assessment of ‘quality of education’.
Advocates say the changes will be “era-defining,” incentivising schools to revamp their curriculums and changing how school leaders think of their roles.
But critics have questioned whether Ofsted can be neutral when assessing curriculums, arguing the schools watchdog favours knowledge-rich approaches.
Mr Whiteman will take aim at the new ‘quality of education’ judgement in his speech, warning it gives “inspectors too much ground to cover in a single judgement”.
“As it is currently worded, the ‘quality of education’ judgement could accidentally promote just as much fear, drive just as much perverse activity and increase workload just as readily as the old set of judgements have done,” he will say.
Mr Whiteman will also urge school leaders to take part in Ofsted’s consultation on the framework, warning they could miss a “golden opportunity”.
“Let me be clear; I’d like to see a new inspection framework, but the detail needs to support the broad ambition. If not trust will be lost,” he will say.
“We will be back to the start with imperfections that are destructive rather than supportive of school improvement.”
A spokesperson for Ofsted said the new "education inspection framework will be the most evidence-based, research-informed and tested framework in our 26 year history" when it comes into force in September.
"The new education framework aims to create a more collaborative inspection, which reduces workload for teachers. We do not want schools to be providing inspectors with internal progress and attainment data of current children or students," said the spokesperson.
"The proposal for on-site preparation will also mean inspectors will have more time to observe classroom teaching and talk with school leaders and teachers. This will allow inspectors to fully assess, based on sound evidence, the quality of education judgement.
"We have been speaking to NAHT about the detail of the proposed handbook for many months and look forward to continuing the conversation with NAHT about our proposals and to their response to our consultation. It’s just disappointing that they didn’t raise these issues when we were discussing them with them in the autumn, when in fact they were very positive, including about the draft handbooks we shared with them."