David Hodge, principal of Rangitoto College in Mairangi Bay, Auckland, said NCEA consistently prepared students well for tertiary studies and the workplace.
"They need to be able to plan their time well, to organise themselves, meet deadlines and realise what they do will be assessed in a wide variety of forms, and these are the things that are mirrored when they go into the workplace. So NCEA is proving incredibly effective in life after school."
Mr Hodge said parents were still confused by the qualification but this was gradually improving. "Initially it was such a radical shift that it took the community a lot longer than everyone predicted it would. Parents are becoming much more familiar with it but it's still a challenge."
Bradley Fenner, headmaster of King's College in Otahuhu, said only about 30 per cent of the school's students undertook NCEA. The rest participated in the Cambridge International Exams, a system based on exams and not internal assessment.
Mr Fenner said the school did not favour Cambridge over NCEA but he believed the higher acceptance of Cambridge exams harked back to the "uncertainty" around NCEA when it was introduced.
"Because it was so different, I think it was hard for parents to come to terms with. We all grew up with marks and percentages and grades and you move to a system based on credits, it was just a foreign language."
Mr Fenner said parents previously struggled to understand NCEA but over time the confusion had reduced.
Hillcrest High School principal Kelvin Whiting said his Hamilton school held an annual evening class for parents whose children were entering NCEA, to help them understand it.
Mr Whiting, an executive member of the Secondary Principals' Association of New Zealand, said NCEA was still referred to as "School C" in the first few years.
He believed NCEA was working well now, but said it was true that teachers felt burdened by the heavy workload, part of which was caused by the opportunity for students to resubmit internal assessments.
Mr Whiting also pointed out that students could work the system by using it as a "credit collection" rather than a tool for learning.
"Students become more worried about gaining the credits than the actual learning that takes place. They become quite savvy and selective about what they're doing."
Now with a target from the Government for 85 per cent of 18-year-olds to achieve NCEA Level 2 by 2017, Mr Whiting said this would add pressure to schools.