Headteachers have spoken of "dramatic" levels of learning loss among exam cohorts this year revealed by mock exams and catch-up tests.
The warnings come amid an ongoing debate over whether more needs to be done to mitigate the effects of Covid-19 on students sitting exams in the summer of 2021.
The Association of School and College Leaders asked members for their insights into how much learning has been lost by Years 11 and 13 during the pandemic.
The responses, shared with Tes, reveal startling disparities in attainment among these groups of students due to sit exams next summer.
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One headteacher reported that, having completed assessments for Year 11 across all subjects, their view was that "grades are almost a grade down on where we were at this time last year" – or 0.7 of a grade on average.
They added that "by far the greatest problem is trying to put together an action plan with 34 students from Year 11 that are self-isolating and being taught remotely".
Another head reported that, compared with their last five years' data at October half-term, they were seeing "what equates now to a Progress 8 score prediction of 0.3 lower than at the same assessment point in previous years".
"I know, talking to some schools, there are heads that won't even entertain trying to calculate this at present for fear of what might be the case for their cohorts," they added.
Coronavirus: Disruption 'simply too great' for GCSE students
The head said that the current cohort of Year 11 students had missed more learning than the previous year, because in the first lockdown of 2020 most academic courses were beginning to move on to assessment and revision structures, whereas Year 11 this year had experienced "slower" progress over lockdown.
"Despite after-school sessions, smaller group intervention and one-to-one tutoring in school additional to the main curriculum lessons, I question if this will be enough across the country," they said.
"With Year 11 cohorts out on isolation in a couple of schools I know of this year for up to three weeks already, and ours out for a two-week period with online live lessons, I worry that the disruption is simply too great to expect national performance to be as it would have been."
The comments reflect fears expressed by other school leaders and teachers, especially those in parts of the country worst affected by the pandemic, who have suggested that more needs to be done to mitigate the impact of Covid-19 on exam cohorts.
In October, headteachers in the Liverpool City region called for greater "signposted" choice in exams to mitigate the impact of local lockdowns.
However, last week heads said that greater "optionality" and choice in 2021 papers was now "unlikely", although students might be able to see material from exam papers in advance.
Ofqual is due to announce final plans for the 2021 exam series by the end of November.
Other heads in the ASCL survey pointed out the disparities in students' learning based on how much remote education they had accessed during the lockdown.
One head said that, while students who were "previously diligent and engaged" had returned to school mostly "where they should be", or even, in some cases, "enriched" by the lockdown because of greater opportunities for independent study, "those who were already disengaged and struggling return more lost, more disengaged than they were previously, having done little to nothing over the six months of lockdown".
They also said that attempts to assess students' current levels of attainment have proved "devastating" on mental health.
"Aware of what happened last year, the pupils now see every mock as possibly determining their GCSE grade and whisper the word CAG [centre-assessed grade] in the corridor," they said.
Mental health fears for students
"This is causing even diligent and measured students to see every test as a possible GCSE, resulting in a never-ending feeling of being weighed and measured, despite how often the idea of formative assessment is discussed. The mental health burden on the current Year 11 and 13 is going to grow and grow with the uncertainty of whether exams will go ahead (and nobody trusts the government’s word that they will!)."
And others have highlighted how year groups being sent home in temporary isolation is compounding the issue.
"This week I have sent home 40 and then another 20 Year 11 students," one head reported.
"Their mocks are in two weeks’ time. Their anxiety, already high, is now through the roof as they are all scrambling to make sure they can access our remote lessons. Staff are now teaching eight students in a class, with a further 15 or so online at home – the pressure to ensure all students get a fair and balanced curriculum delivered is immense," they added.
Some heads have reported that while students have retained basic knowledge from lockdown, higher-order skills needed for the exams have not been absorbed.
In English literature, for example, one head said that lockdown work had focused on knowledge and understanding of key quotations, characters and themes, with mock marking showing that this knowledge was "secure".
However, when it came to language analysis, "there appears to be a dramatic loss of learning".
"Students find this element hard. Remote learning tasks which tried to address it had very little uptake and students have suffered from a lack of direct teaching," they said.
Learning lost in lockdown
"This is being addressed through our interleaving, study support and teaching of other course elements, so the ground can be made up. However, the mock results themselves show a dramatic loss, even if the reality is more nuanced," they added.
Heads also pointed out that the learning loss has not been evenly spread across the country, with one stating that "the concentration on Covid-19 in areas with the highest number of vulnerable students without adequate access to IT means that they are feeling learning loss more acutely".
However, they added that their own Year 11 cohort's English mocks showed potentially better performance than in previous years, perhaps because students feel their mock grades could influence centre-assessed grading later in the year.
Not all heads who commented said they had seen significant levels of learning loss among exam cohorts.
One head said they realised their school was "in a very privileged position but we have not identified any significant loss of learning", as their students had been kept on track over the lockdown via live lessons, and they had not needed to isolate any year groups.
"I am sure it is only a matter of time but for now exam groups and other years are on track," they said.
Another added: "I would say that the emphasis on learning loss has been grossly overstated and that the government has probably spent a lot of money unnecessarily to fix a problem that was never that great in the first place."
They said their school had calculated that its students made 50 per cent of their progress in Year 11, so that the "least productive" part of the year had been lost over the lockdown.
"Our current Year 11 are about 0.4 of a grade behind where they were this time last year," they said.
However, many cautioned that Year 11 and 13 this year were more "adversely affected" by the pandemic than the year above them.
"We run a good programme of remote learning via Google Classroom and teachers soon got used to having half the group in and half out at home on the end of a Google Meet – but it's not the same (obviously!) especially when the courses are covering difficult concepts," one head said.
"I think these year groups have been more adversely affected than last year's [Year] 11 and 13 as the first year of their course was spent half in lockdown and now this.
"These pupils are in no way getting the same experience as pupils in other schools who have had very few Covid cases and perhaps no periods of self-isolation, and for them all to be examined...in the same way, without this being taken into account, seems unbelievably unfair."
Another head said that the situation was becoming "bleaker by the minute".
"We have been fairly lucky so far with upper school Covid cases, but we have lost 38 Year 11 students for two weeks and despite our improved remote learning programme, this can’t replace actual teaching," they said.
"The students are worried about their GCSE exams and we are seeing student absence increasing weekly, as many can’t cope with the uncertainty of the exams and the pressure of trying to catch up."
Geoff Barton, general secretary of the Association of School and College Leaders, said: “The feedback from school leaders shows mixed experiences of the extent to which pupils have lost out on learning as a result of the first national lockdown and the ongoing disruption that is taking place."
Some students benefited from parents being available to support them more during the lockdown, while some will not have had access to a dedicated laptop or a stable internet connection, he said.
The solutions, he said, were "to allow schools to get on with the job of identifying learning gaps and providing tailored support without the added burden of Ofsted inspections and performance tables". In addition, he wanted assurance that, if exams are to take place next summer, "they take account of these highly variable learning experiences".
Jill Duffy, chief executive of exam board OCR, agreed that there was a "broad spectrum of learning experiences across the country".
She said: "We feel we’ve got a really good understanding of the circumstances and challenges that pupils, their parents and schools are facing and we’re thinking hard about how assessment and awarding can accommodate them, including the sorts of contingency arrangements that may be required, the awarding standards that should be adopted and the more general support we can offer."