No private school pupil sat national reference tests this year, which means they are unlikely to show why the sector had the biggest jump in top GCSE and A-level grades.
The finding casts doubt on the usefulness of the NRT, which is run every year to monitor over time how well cohorts of pupils are performing.
The government has been criticised over the rise, with ministers facing more questions from MPs this week.
It is not known whether the higher results reflect that poorer pupils were more likely to have their education disrupted by Covid, or are a result of the teacher grading system used this year.
Schools Week understands not a single private school took part in this year’s NRT, leaving Ofqual unable to reveal the true reasons behind the rise.
Sarrah Raffray, the headteacher of St Augustine’s Priory, a private school in Ealing, west London, said it was “extremely odd” that there was a data set on learning loss without the independent sector in it.
“It makes the data less meaningful – it doesn’t make sense,” she said. “It perpetuates the problem of narratives on what is perceived to be driving the gap, without the evidence.”
The year 11 test in English language and maths at about 300 schools usually helps to set standards at GCSE. The sample is based on school size and prior GCSE results.
Tests used to ‘identify gaps in learning’ this year
But because exams were cancelled this year, Ofqual said the test instead would “identify gaps in learning for catch-up planning, identifying patterns to see how things differ from normal years”.
State schools in England must take the test if asked, but it is voluntary for independent schools. However, private schools pupils are asked to take part to ensure the test sample is nationally representative.
Eight private schools took part In 2018, rising to ten in 2019 before dropping again to six in 2020. Ofqual has refused to publicly reveal the data for 2021 until results are published in the autumn.
Jo-Anne Baird, an Ofqual adviser who sits on the regulator’s NRT sub-group, said: “There’s a question about whether [the law] should apply to all schools.”
Absence data shows that poorer pupils missed 30 per cent more school days last autumn than their better-off counterparts, which supports the argument that the gap reflects the pandemic.
But a Sutton Trust report also found that teachers at affluent schools were more likely to be pressured by pushy parents to boost grades.
Minister insists bigger private school grades rise ‘a consequence of the pandemic’
Appearing before the education select committee on Tuesday, Nick Gibb, the schools minister, said the bigger rise in top grades for private schools was a “consequence of the pandemic, rather than the awarding system, [which has], of course, hit children from more disadvantaged backgrounds harder than it has for children from more affluent backgrounds”.
But Ian Bauckham, Ofqual’s interim chair, said it was “impossible” to say that the changes were “simply due to the pandemic or simply due to the approach we’ve taken in grading”.
National standardised tests were the only way to know for certain the underlying changes in attainment trends for disadvantaged pupils.
Bauckham said the NRT results would be able to “give us some objective reference points on actual underlying standards”, despite a “reduced number” of schools taking part this year.
Caroline Derbyshire, the chair of the Headteachers’ Roundtable, said the gap was a “scandal”.
“It may well have widened not because students in independent schools achieved more, but because their schools awarded more high grades and they did not fear the consequences of doing so.”
Lack of private school participation ‘surprising’
But Barnaby Lenon, a former Ofqual adviser and chairman of the Independent Schools Council, said it was “nothing to do with the assessment system this year”.
He was “surprised” no independent schools took the NRT, as they were a “significant subset”. He urged exam boards to look at teacher assessed grades to see what was driving the gap.
Raffray suggested that private schools may have had less resource to carry out the test in the context of the pandemic.
Ofqual refused to comment on any NRT data from this year. A spokesperson said: “The NRT will be used this year to identify gaps in learning for catch-up planning, identifying patterns to see how things differ from normal years. We are really grateful to the schools that took part.”