However, the research, carried out by YouGov on behalf of Ofqual, the exams regulator, found that the pace of change in qualifications and examinations was a major cause of concern in schools, leading to disquiet among professionals.
Almost 3,500 heads, teachers, students, parents and members of the public were interviewed as part of the survey.
It found that nearly half of teachers lacked confidence in A level grades, and a similar proportion believes marking has become less accurate over the past two years.
But the majority of heads (81 per cent) and teachers (74 per cent) had confidence in A levels overall.
When asked what percentage of candidates they thought got the right A level grade, heads said between 71 and 80 per cent of students achieved the grade they deserved.
One of the main concerns about the exams system as a whole appeared to be constant change. The study found that “changes made to GCSEs in the last 12 months” was repeatedly quoted by all respondents, except members of the public, as the main reason behind their evaluation of Ofqual’s performance as ineffective – including 67 per cent of headteachers, 56 per cent of teachers, 48 per cent of students, and 46 per cent of parents.
Furthermore, the research found that “inconsistent marking” of exam papers and “inconsistent grading” were among the reasons why both headteachers and teachers believed the regulator to be ineffective at maintaining standards. Concern was also expressed at the “removal of the January assessment opportunity/January exams”.
Russell Hobby, general secretary of the National Association of Head Teachers, said: “Falling levels of confidence in the system among school leaders and teachers indicate both concern about the current structure and apprehension about both the content and pace of change. Ofqual faces the urgent task of addressing matters causing disquiet.”
Brian Lightman, general secretary of the Association of School and College Leaders, added: “This report gives hard evidence to back up what we have been saying for many months. The strong reputation of GCSEs is being eroded by constant, piecemeal change. Parents and students are confused, employers are frustrated, and teachers are overwhelmed.
“We had changes to GCSE exams in some subjects this summer, there are more changes to other subjects coming next summer. Then there is the move to 1 to 9 grades for some but not all subjects the following summer, followed by numerical grades for the remaining subjects the following year.
“With the move to 1 to 9 grades, Ofqual needs to set out very clearly what is needed to achieve a specific grade. This is not the same as describing what statistical proportion of students will achieve a grade.”
The report also found that heads and teachers reported the highest level of knowledge and understanding of vocational qualifications, with the public having the least understanding.
More than three-quarters of heads and two-thirds of teachers said they knew the difference between GCSEs, A levels and vocational qualifications. All respondents believed that “other qualifications” including vocational ones, were easier to pass than GCSEs and A levels.