The revelation has sparked speculation that grade 5 might become the new government-set benchmark for what constitutes a “good” GCSE.
It comes after exams regulator Ofqual published its plans for how the new-look GCSE grades of 1 to 9 will function.
The new grades are to be used with reformed GCSE qualifications, the first three of which (mathematics, English language and English literature) are to be taught from 2015, with the first results in 2017.
After holding a consultation, Ofqual has decided that the grade 3 to 4 boundary on the new-look scale will align with the D to C grade boundary.
There will also be an alignment between the grade 6 to 7 boundary and the present grade B to A boundary.
Notably, the top 20 per cent of those scoring above grade 7 will be awarded a grade 9.
The bottom of grade 1 on the new scale will be aligned with the bottom of grade G.
Grade 5, meanwhile, is to represent the top third of marks for a current grade C and the bottom third of marks for a current grade B.
This will, Ofqual has explained, create a benchmark that will match up with the average achievement in other leading nations within the Programme for International Student Assessment (PISA) tables.
An Ofqual explanatory paper states: “By positioning the new grade 5 in the top third of the marks for the current grade C and the bottom third of the marks for the current grade B, it will be of greater demand than the present grade C.
“If students presently achieving grade Cs were to achieve grade 5s, that may be broadly in line with what would be required to match the average performance of 16-year-olds in England with the PISA mathematics performances of countries such as Finland, Canada, the Netherlands and Switzerland.”
Chief regulator Glenys Stacey added: “From our formal consultation and conversations with teachers and parents, we know some people may not have fully comprehended our plans for grade 5 and international comparisons.
“To try and clarify this, it is not about putting in place any direct links or ties to any grades set elsewhere. Rather, where grade 5 sits within the grading scale will place it above a current grade C, and broadly in line with what the best available evidence tells us is the average performance of 16-year-olds in high performing countries.”
Ms Stacey also warned against making direct comparisons between the numerical grades and the current system: “We do need to caution against direct comparisons and overly simplistic descriptions of the approach.
“For example, it is not right to say simply that a new grade 4 will equal a current grade C. The read across is at the bottom of each grade, so that broadly the same proportion of students will get 4 and above as currently get C and above. A subtle but important difference.”
Brian Lightman, general secretary of the Association of School and College Leaders, said that Ofqual must now “set out very clearly” what is needed to achieve a specific grade.
He continued: “Employers need a clear message that if a student has achieved a particular grade, it means that they have a certain skill or knowledge level. There will be a large number of students who end up with both letter and numerical grades so it is important to have a benchmark that shows how the two relate.
“We do have concerns about limiting the proportion of students who can get the highest grade. If students achieve at a very high level that should be recognised. Where standards have improved, the results must reflect this. Schools must be fully briefed and provided with specimen papers and examples of questions in advance of implementation.”
Dr Mary Bousted, general secretary of the Association of Teachers and Lecturers, warned that in 2017 and 2018 students will be sitting a mixture of new-style GCSEs graded numerically and old-style exams graded with letters.
She added: “Students sitting GCSEs in 2017, 2018 and 2019 will be the guinea-pig generation, forced to test drive reforms this government’s has failed to trial.”
Elsewhere, Ofqual has confirmed that the new maths qualification is to be tiered and that grades 4 and 5 will be available through both tiers.
You can download Ofqual’s full technical explanation at http://ofqual.gov.uk/news/setting-standards-new-gcses-2017/