Under major reforms set to be introduced in August, pupils will no longer receive traditional A*- G grades. Instead, exams will be marked from nine to one, with nine representing the highest result.
Supporters of the scheme have argued that the move will allow more differentiation between students.
But representatives at teaching union NASUWT’s annual conference said the new grading system will encourage more “teaching to the test” by moving the goalposts on what is considered a “good pass”.
According to exams watchdog Ofqual, a grade four will be aroundthe equivalent of a C under the current system, whereas a grade nine will be better than the present A* score.
“The changes to exam grading have created huge uncertainty for pupils, teachers, parents and employers which will be difficult for schools to manage,” NASUWT general secretary Chris Keates said.
“Schools already buckling from excessive workloads are now facing even more bureaucratic reform and young people, already experiencing rising rates of anxiety and mental ill health, will face even greater pressure to perform.”
A poll by the teaching union found that schools are struggling to deal with students’ mental health issues, with 84% blaming pupils’ problems in part on exam pressures.
Keates added: “These changes have been driven by political imperative, rather than the needs of young people.
“The government has consistently sought to portray GCSEs as ‘broken’ and ‘dumbed down’ qualifications in order to push through its vision of an elitist, narrowly focused curriculum and qualifications system which risks failing to meet the needs of the majority of young people.”
But a spokesperson for the Department for Education defended the reforms, saying the new grading system would provide “greater stretch” for the highest performers.
They said: “These changes will help young people to compete with the best in the world and deliver the skills that employers tell us they need.
”Nothing has changed with regard to schools being held to account for the proportion of children achieving a strong pass and we are working with Ofqual to support teachers as we implement the new system.”
The one to nine grades will only be given for English language, English literature and maths exams in 2017, with other subjects moving over to the new grading system in 2018 and 2019.
During the transition, students will receive a mixture of letter and number grades.