Teachers' NCEA grading has improved significantly, a major review has found, but it said many of them wanted clearer guidelines and support from the national education body.
A report by the Auditor-General on the consistency and quality of NCEA assessment said moderators were increasingly agreeing with secondary school teachers' grading of their students' work.
However, it found teachers wanted more support from the New Zealand Qualifications Authority (NZQA) to help them assess students' work against the national standards.
A survey of 1780 teachers found 61 per cent wanted more access to resources such as workshops which showed them the best way to grade their students. Teachers found annotated exemplars - examples of students work and how it was marked - the most useful resource from NZQA.
But many also complained that the exemplars contained errors or arrived too late in the year to be useful for teachers.
The Ministry of Education and NZQA admitted to Auditor-General Lyn Provost that there had been problems with producing the exemplars, but this process was being repaired.
NZQA was also improving its website so that exemplars were more accessible.
A number of teachers complained that the external moderation of their grading was inconsistent year to year, and often did not give advice on how to resolve problems.
Moderators told teachers whether they had marked work too strictly or leniently.
Mrs Provost said: "There is always likely to be some disagreement, given that interpreting standards and assessing students' work must involve some subjectivity."
Her report concluded moderation was generally of a high standard and useful to teachers.
In 2008, when public confidence in the NCEA system was at a low, a third of NCEA marking examined by moderators failed to meet national standards.
NZQA data showed that had fallen to 17 per cent in 2009 and 9 per cent in 2010.
"This indicates the effect that NZQA is having on improving the consistency and quality of teachers' setting of tasks and internal assessments," Mrs Provost said.
The greater consistency in marking was credited to the introduction of fulltime moderators. NZQA now employs 34 permanent moderators and 235 part-time moderators.