The survey by the National Union of Teachers of 1,250 heads found that only one in five felt that inspections led directly to improvement. On the contrary, staff lost motivation and were so tired that pupils' learning suffered.
The criticisms are the latest in a series from heads and teachers as the Commons Education and Employment Committee continues its investigation into Ofsted.
One head said: "Although our report was relatively good, it took my staff eight months to start operating again at a normal level. This was to the detriment of their classes."
Another said: "Staff were under stress in the period leading up to the inspection, which did nothing to improve teaching, and the focus of the school shifted away from our work with the children towards paperwork and policy documents."
A third said that teachers who made an effort and "stage-managed" the event did well. Some good teachers, on the other hand, who allowed inspectors to take them as they found them, did not do well.
Heads were evenly divided on whether inspectors made fair and accurate judgementsand on whether they took sufficient account of pupils' backgrounds and schools' histories.
Doug McAvoy, the union's general secretary, said: "The extra stress and workload created by Ofsted inspections might be justified if the process and outcomes were valued by teachers and led to school improvement. But head and deputy head teachers clearly do not believe that is the case."
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