to add to what I said earlier, the two school I have been in that "failed" ofsted were both far better schools than the one graded outstanding.
Some real life examples - a 16 year old applying for the armed forces - one of the requirements for his application was that he was in full time education when he applied , so he wanted to start in our sixth form. This meant he could apply to the armed forces, and he could continue with us if his application failed. An outstanding school would have turned him down, afraid he would impact on their retention statistics. The failing school took him. Same for other students that could mess up attendance and retention data, refugees, a child with cancer, etc
Offering every child a fair chance actively counts against you in ofsted gradings.
Another example - a primary school, with an ofsted inspector, comes to use secondary school sports facilities - the teachers with the primary school children are known to the receptionist, and she normally waves them through. On this occasion, she asks to check the id of the ofsted inspector. Fair enough. Next day, same teachers come with different children, and same ofsted inspector. Receptionist recognises inspector from day before, waves whole group through.
Next thing, SECONDARY SCHOOL informed they have "failed" ofsted, because the receptionist didnt check the id of the inspector she recognised from the day before. Emergency inspection trigger for secondary school, which never actually happened, so they remained classed as 4
totally meaningless, and caused recruitment problems, with massive knock on effects to the staff