KEY POINTS:
About one in three parents admit they still don't understand the national exam system six years after it was introduced - and only a third support it.
A major survey by the New Zealand Council for Educational Research, due for release today, found the proportion of parents who understand the controversial National Certificate of Educational Achievement system had not improved in the past three years.
The majority of principals and teachers thought employers also had trouble understanding the NCEA.
Half the teachers and 40 per cent of principals were unsure if universities understood the NCEA, under which students gain a combination of credits that are assessed either by schools or externally.
The NCEA did win the backing of 89 per cent of principals and 59 per cent of teachers in the research.
New Zealand Qualifications Authority deputy chief executive (qualifications) Bali Haque said more work was clearly needed to make sure parents understood.
He was confident acceptance of the major shift in thinking would happen over time. "My advice to parents would be to go with the principals, who overwhelmingly support it."
The study found 95 per cent of principals did not want to return to the previous system and just 10 per cent supported the development of a new one.
Mr Haque said a series of changes to the NCEA had been announced since the survey was done last year, including measures to address concerns from parents about the way the system motivated students to do well.
He did not think there was an issue with parents, employers and universities understanding the "nuts and bolts" of NCEA, such as how to read results.
The authority heard of "very few" problems with students making the transition from schools to universities.
The study found evidence of students in their first years of high school earning credits to "bank" until Year 11. It said although the practice could give students a head start, it risked pushing assessment pressure on to younger students.
Chief researcher Rosemary Hipkins said principals in 76 per cent of schools reported credit banking where possible.
"They are exposed to that very formal assessment several more years running," said Dr Hipkins.
"The potential is there to get heartily sick of it."
Mr Haque said the practice was fine if students had reached a certain level and it could be useful for extending students.
"The whole point of NCEA is to provide flexibility and to allow students to be assessed when they are ready."
Workload for students was a worry for 10 per cent of parents, who said the NCEA caused their child too much stress.
Hidden costs in implementing the system were cited by 91 per cent of principals.