While the malady is obvious, the cure is more difficult than solving the hardest of the questions faced last year by 15-year-olds across the country.
While the cry for a back-to-basics approach has an element of truth, a reversal to the teaching methods of yesteryear will create difficulties.
Although there were problems in New Zealand this time with how properly schools and pupils took the testing, the results from the OECD Programme for International Student Assessment (Pisa) are analysed by education authorities.
The questions use knowledge to solve problems, not like simple standardised tests. Crucially, they provide comparisons across time.
New Zealand Principals Federation head Leanne Otene said the results were "absolutely something we need to take seriously".
She noted that while high achievers continued to achieve at high levels above the OECD average, the "tail end of lower achievers has grown, with a high number of children falling into that category".
One particularly concerning piece of data showed the gap between rich and poor tamariki had grown.
New Zealand has shown steady declines since 2009, with the 15-point fall in mathematics since 2018 alarming.
About 690,000 pupils across the world took part. New Zealand scored 479 against the OECD average of 472 in mathematics, 501 in reading (average 476) and 504 in science (average 485).
New Zealand maintained its place above more than half the countries thanks to falls elsewhere. The OECD said mathematics and reading skills are in unprecedented decline across dozens of countries.
The organisation’s education director said Covid probably played some role but should not be overrated.
The long-term decline in several countries "indicates that long-term issues in education systems are also to blame".
New Zealand’s figures might have been boosted because testing here was skewed towards the top international quintile of the socio-economic scale. It also happens that the Pisa 2022 mathematics framework aligns well with the NZ curriculum. This country was also, the OECD said, relatively well prepared for remote instruction.
New Zealand was once a standout for reading. Moving back to "structured literacy" is under way. That should help.
Solving maths problems is built on a solid foundation of numbers and using them. More emphasis on being adept in these basics should surely assist. The Government’s requirement for primary and intermediate schools to teach an hour of reading, writing and maths a day might not alter what often already occurs. It does, however, send a signal about the emphasis for all teachers everywhere.
Homes and parental support have always been crucial. However, many parents lack the motivation (for all sorts of reasons), skills or wherewithal to provide that backing.
Schools sometimes have enormous slack to make up and disadvantages to try to combat. Engaging some pupils in any sort of education can be a huge task.
Poverty need not, though, condemn pupils to poorer performance. New National MP James Meager’s success attests to that. He praised his mother’s dedication and belief in education in his parliamentary maiden speech. The "part-Māori boy raised in a state house by a single parent on the benefit" now represented a rural South Island electorate, Rangitata. It is positive the Government recognises hungry children will struggle to learn and that food in schools programmes should continue, albeit targeted.
Hopefully, the wrap-around-services model for failing whanau can be developed so the children have a chance.
Pisa illustrates again the socioeconomic success skew in society. This, of course, affects slices of Māori and Pasifika, and many others besides.
Despite Australia moving into the Pisa top 10 thanks to others falling, it has its concerns about educational standards.
It is proposed to overhaul the way teachers are taught. That could be part of the mix here. Although no-one should pretend it will be easy, New Zealand for the sake of its children and its future must halt and reverse the slide in education standards.