A headteachers’ union fears that Ofsted’s crackdown on off-rolling will undermine schools’ ability to carry out managed moves of pupils.
The Association of School and College Leaders says schools may be reluctant to carry out such moves of children to other schools for fear of being penalised by the watchdog.
Ofsted is likely to downgrade schools who off-roll pupils - removing them from their rolls without an exclusion for the benefit of the school rather than the student.
But ASCL is now concerned that Ofsted's "opaque" definition of what off-rolling is will include managed moves, which the union says schools are carrying out legitimately.
Quick read: Heads warn of off-rolling confusion
Analysis: Mixed messages on off-rolling
Background: 55,000 unexplained moves
Heads' fears have been sparked by a recent Ofsted blog suggesting that inspectors could examine the motives behind any managed moves as part of their focus on off-rolling.
The post says: "Managed moves from one school to another as an alternative to exclusion can sometimes be effective in breaking the cycle of poor pupil behaviour. If these moves are used in pupils’ best interests, with the agreement of everyone involved within the statutory guidance, then again, this is not off-rolling."
Stephen Rollett, ASCL's inspection specialist, told Tes that it had raised concerns that inspectors would be deciding in each case whether managed moves were carried out for the benefit of the school or the pupil - and therefore whether it could be classed as off-rolling.
He said: “We have always understood off-rolling to mean the illegitimate practice of putting pressure on families to take their child out of school to improve the school’s results. This is an easily understood definition and something which is obviously improper.
“However, Ofsted has extended this definition to encompass any removal from a school roll which it decides is primarily in the best interests of the school, rather than in the best interests of the pupil. It suggests that inspectors will look at managed moves from one school to another and whether these are in the best interests of the pupil.
“In my experience managed moves are something which is carried out by schools in the interests of the pupils, often with pupils who have complex needs and it is done to avoid the need for exclusion. It is an example of schools working in partnership.
“However if managed moves are going to fall within Ofsted’s focus on off-rolling and it is going to come down to the judgement of an inspector I am concerned what this will mean for schools' willingness to carry out managed moves and what this will mean for the pupils who would benefit from them.”
Ofsted’s official definition of off-rolling is: “The practice of removing a pupil from the school roll without a formal, permanent exclusion or by encouraging a parent to remove their child from the school roll, when the removal is primarily in the interests of the school rather than in the best interests of the pupil.”
An Ofsted spokesperson said: "The Education Inspection Framework makes clear what could constitute off-rolling, a definition that was accepted and used in the recent Timpson Review. There can be no hard and fast rules about how it should be addressed.
"That is why inspectors will take into account a wide range of evidence when considering the issue. When appropriate, they will ask school leaders to explain how a move was in a pupil’s best interests.
"Ofsted has stressed that decisions taken in the best interests of pupils are not off-rolling, and neither are permanent exclusions when done properly."
Ofsted has already identified 300 schools with high pupil movement which it said could indicate off-rolling. However, it has declined to name them based on this data.
So far it has identified off-rolling in three published inspection reports. Two of these schools, Harrop Fold from TV's Educating Greater Manchester and Shenley Academy in Birmingham, were judged to be "inadequate".
However, the inspection report into Discovery Academy in Stoke-on-Trent provoked debate as the school was rated "good" but found to be off-rolling.
Pupils were taken off the school's roll in Year 11 after being moved to alternative provision.