Concerns have been raised by secondary teachers after pupils who left their schools years ago were included in provisional data used by the Department for Education (DfE) to measure performance.
Schools were given access to their provisional score for Progress 8 – the government’s headline accountability measure – this week, ahead of the national league tables being released in October.
Already a number of schools have published these scores online – but some staff are unhappy with the accuracy of the data sent over on Monday.
Staff took to social media to express their concern after they noticed that pupils who had been taken off the school's roll before January this year had been included in their data:
Earlier this year, Tes revealed that a growing number of heads have raised fears about how much a school’s overall Progress 8 score can be distorted by poor performance from just a handful of pupils.
The measure, based on average progress across a school, means that pupils who take no exams, or hardly any, can do significantly more damage to the school’s overall score than under previous measures.
Progress 8 roll changes
Today the DfE said it would remove pupils that had been taken off a school’s roll before the 2017 census from the data, after the issue was raised by schools.
A statement on the DfE's school checking website said: "It has come to our attention that recent changes to the way we calculate pupils at the end of key stage 4 studies have caused some pupils to appear on the school roll, when they were recorded as off roll in the 2017 spring census.
"Pupils who took exams in 2017 or have a census record at the school for a previous year have been included in the schools' pupil data and number on roll.
"These pupils will be automatically removed from the number on roll figure for publication of provisional results in October."
It added that schools would be contacted via email with further guidance.
Duncan Baldwin, deputy policy director at the Association of School and College Leaders, said the issue had been raised by the union's members this week. He said it was "not helpful" and added that "the concern about public accountability is a serious one."
But Mr Baldwin said: "The DfE know that there is an issue. They have acknowledged that and they will act on it and they are taking the right steps to sort it out.
"It is nothing for schools to be alarmed about. This is such a large and complex exercise, so there's bound to be some errors that creep in."