When an international report shows New Zealand's maths, science and reading scores for 15-year-olds are in "absolute freefall" - to quote Labour's education spokesman, Chris Hipkins - two questions emerge. One is, can we trust the test results? The second question is: if we can, what should we do about it?
New Zealand fell this week from 7th to 13th in reading, from 7th to 18th in science and from 13th to 22nd in maths in the OECD's Programme for International Study Assessment (Pisa) report for 2012. The drop can be only partly explained by the inclusion in the last decade of new city states - Shanghai-China, Hong Kong-China and Macau-China - which have test-based education systems and tend to dominate the top of the rankings.
Some critics have pointed out the international country rankings are highly suspect, as the test results combine real data with computer-generated "plausible results".
Danish statistician Sven Kreiner told the Listener this week that this unreliability could swing Japan's reading ranking anywhere between 8th and 40th and Britain's from 14th to 30th.
However, most experts agree that a country's results, over time, tell a more reliable story and New Zealand is also slipping here.
Our scores have declined in all three subjects and the biggest drop has occurred in the past three years. Maths has consistently fallen from a mark of 537 and a ranking of 4th in 2000 to 500 last year, barely above the OECD average. The trend is consistent with other recent national and international results. In the 2011 Trends in Mathematics and Science Study (TIMSS) published a year ago, New Zealand 9-year-olds finished bottom-equal among developed nations. Half were unable to add 218 and 191.
National testing shows the number of Year 8 (12-year-old) pupils who could answer a series of simple multiplication questions correctly within four seconds dropped from 47 per cent in 2001 to 37 per cent in 2009. Science results published two weeks ago show that only about 20 per cent of Year 8 pupils were at or above their expected curriculum level. University and polytechnic engineering schools have also complained they cannot fill their places with local students because most lack basic maths skills and need extensive remedial help.
Victoria University engineering school head Professor Dale Carnegie has blamed NCEA for failing to prepare students for the intellectual rigour of university study.
Education Minister Hekia Parata says she is encouraging teachers to improve the way they track students' progress all the way through primary and secondary school, including an awkward gap in the first two years of secondary school when National Standards assessment has finished and NCEA has not yet started.
But she does not agree with critics who say the new maths curriculum - which began when the 15-year-olds tested last year started school - neglects basic arithmetic skills in favour of problem-solving.
She points to a combination of problems which disadvantaged this age group. Parata says the new curriculum started just as schools faced a staff shortage and had to hire many overseas-trained teachers and beginning teachers trained in university courses that focused on academic ability.
The Government has since "raised the bar" for teacher entry, put more emphasis on practical classroom skills and is spending $10.5 million to boost maths and science teaching.
The Prime Minister's chief science adviser, Sir Peter Gluckman, says research shows many primary teachers enjoy teaching science but lose confidence in their ability to answer children's increasingly complex questions as they get to intermediate level. He thinks teachers need to be better prepared for this complexity and the curriculum has to be presented in a way that engages children.
The third crucial step, he argues, is that families and communities have to value science - something Asian countries are well known for but which has not been common in New Zealand.