Jonathan Taylor, headteacher of mixed-ability North Bridge House Senior School in London, is warning that many students struggle with the academic nature of exams.
With GCSE exams predominantly writing-based, students who tend to excel more creatively aren't able to achieve the top grades.
Mr Taylor suggests that this assessment method means that bright students - often males - struggle to communicate their answers.
"A lot of students have got great creative ideas but do not have a natural ability to express these succinctly in an exam formula," he said.
"Many who are very capable in what they can express orally are losing their confidence."
With the number of students choosing vocational courses for GCSE and A-levels continuing to rise, it could be that other methods of exams could help some students in core academic subjects.