An OECD report into New Zealand's education system has been met by cries of victory from both sides of the National Standards argument.
The Government introduced the school assessment framework in 2010, saying the standards would provide better information so extra help for schools could be better targeted.
However, there have been strong protests from teachers and schools, who say setting achievement standards will do nothing to boost student performance and could negatively affect children who do not meet them.
An OECD review of evaluation and assessment in New Zealand education has not come down firmly on either side of the argument, saying that while many aspects of the standards fit well with the country's approach to assessment, their implementation was a matter of concern.
Union concerns that the system has been implemented too fast were echoed in the review, which said "there has not been enough time to build the capacity necessary to ensure the embedding of these", and support for teachers around assessment and reporting needed ongoing attention.
The review, released today, also stressed that the variation in practices across New Zealand raised questions about consistency, and suggested introducing regional education bodies to help improve nationwide consistency.
Education union NZEI said the report reiterated many concerns schools and teachers had been flagging since National Standards were first introduced.
NZEI President Ian Leckie noted in particular the review's recommendation to clarify "what kind of information standards-based reporting can and cannot provide, who should have access to the information and what uses of the information are considered appropriate".
Mr Leckie said the statement was "clearly casting serious doubt on the accuracy of the standards in measuring a school's effectiveness or reflecting a student's learning or progress".
"It sounds the same warning which schools have been trying to give to the government - that any National Standards-based school league tables would be inherently unfair and caution is needed."
The review also outlined a number of benefits to the standards, saying they had the "potential to serve as a common reference for teachers and to ensure the monitoring of progress towards achieving national learning objectives".
Education Minister Hekia Parata welcomed the review, saying it endorsed New Zealand's assessment practices as being high quality and transparent.
"The OECD report says National Standards will improve information about student achievement and progress, and identify the students who need more support," she said.
"It recommends more work is done to implement the standards, which is exactly what we are focusing on now - ensuring the standards are further developed and embedded within our schools."
The reviewers, who conducted their investigation in August, 2010, noted the resistance to National Standards, and said it stemmed largely from a fear that autonomy, initiative and diversity in schools would be sacrificed to common measures and "top-down imposition".
"The implementation of National Standards will be difficult if concerns of schools, teacher organisations and advisory bodies are not attended to and refinements made to the framework and process of roll out."