A series of poor test results has sent New Zealand tumbling down an international ranking of education systems.
The Learning Curve index, calculated by the Economist magazine's Intelligence Unit, puts New Zealand in 16th place, down from eighth two years ago, and just below Australia.
The ranking collates the most recently published scores in international tests of children's reading, maths and science skills, as well as rates of graduation from school and university and adult literacy.
New Zealand children have had a bad run in global exams over the last few years and the ranking says our education system is not as good as it used to be.
But the teacher unions, the Post Primary Teachers Association and the Educational Institute, warn against reading too much into the league table.
PPTA Angela Roberts said the ranking was based on international tests that were not an accurate measure of education success, and were "very narrow measures".
"I think it would be more useful for us to be spending our time looking at what happens to our school leavers; for example do they end up in prison or entrepeneurs on the global stage."
It was commissioned by an education company, Pearson, that had an interest in convincing people there was a need for its help, she said.