A headteachers’ union has pledged to investigate a drop in English GCSE grades after a spate of schools complained of receiving unexpected results.

Today’s national results revealed a drop in the A*-C pass rate, from 63.6 per cent last year to 61.7 per cent in this summer’s sitting, but exam boards warned that some schools faced greater volatility due to key changes introduced this year.

These included speaking and listening not being counted in students’ overall grade for the subject, greater weighting being given to exams and the switch from modules to end-of-course assessment.

Several schools told TES they had been hit by low results, with one teacher reporting that overall grades in the subject were 30 per cent lower than had been predicted.

Brian Lightman, general secretary of the Association of School and College Leaders (ASCL), said high-performing and independent schools were among those affected, particularly those with a high proportion of students around the C/D borderline.

“We want to investigate in depth why it is that some schools - and I’m  talking about schools that are seen as successful, schools which have got good Ofsted reports and a track record of high achievement - have suddenly found this volatility,” he said. “That’s what we need to understand.

 “We’re hearing from schools that have got clusters of Ds, but were also hearing about schools that are reporting a drop at the top end.

“National statistics over an enormous cohort do not tell the story of an individual young person who’s got a [lower] grade. It may be a D rather than a C, or it may be an A rather than A*. That could mean Oxbridge or not, or a Russell Group [university] or not. It could have very serious implications.”

Mr Lightman also warned governors to “look beyond the raw statistics and look at the full story” when analysing results.

Earlier today, former ASCL president Dame Joan McVittie told TES that her school, Woodside High in North London, had seen a drop of 18 percentage points in the proportion of students achieving A*-C grades in English. “They move the grade boundary quite significantly, and take out a lot of my kids. We’re absolutely furious,” Dame Joan added.

In an online survey run by TES, 57.7 per cent of more than 700 teachers who responded said their results had not been “largely as expected”. One response said English results were “30 per cent lower than predicted”, while another said “most students have one grade below expectations” in the subject.

A third teacher said there had been a “marked increase in grade Ds in English language”, adding: “We have never entered students early or had them sit the exam several times. Our [senior management team is] going mad. It’s like 2012 all over again.”

William Richardson, general secretary of the Headmasters’ and Headmistresses’ Conference, which represents leading private schools, said that this summer’s results could have been hit by an “enormous scramble” of “savvy” schools to enter their brightest students in the November sitting.

This was the final opportunity for students to take the previous version of the English GCSE qualification, with a modular form and including speaking and listening in the overall grade. There was a massive 123 per cent increase in entries for this sitting, up to 151,207 from 67,682 in winter 2012, while entries in the subject this summer dropped by 215,000.

Mr Lightman said schools concerned about their results should carefully analyse their data, and consider submitting an appeal to the exam board concerned.

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