New Zealand has recorded its worst ever results in the OECD's Programme for International Student Assessment (PISA) tests of reading, maths and science amid an unprecedented global decline in performance.
This country's 15-year-olds' average scores in the PISA dropped a disastrous 15 points in maths to 479 points, their science and reading scores fell just 4-5 points to 504 and 501 points respectively, and the gap between rich and poor students grew.
The declines continued a long-term trend of falling scores dating back to at least 2009 and happened despite New Zealand's average results being skewed upward by about 10 points due to a low participation rate in the assessments held in term three 2022.
New Zealand was not alone, however. The overall average scores for the 81 countries and economies that participated in the tests dropped significantly in maths (17 points) and reading (11 points) and slightly in science (4 points) since the previous round of tests in 2018.
Considering only the 37 nations of the OECD that participated, average performance suffered a record drop equivalent to about three-quarters of a year of learning in maths and half a year in reading with countries including the Netherlands and Finland experiencing drops of more than 20 points, equivalent to a year's education.
The OECD's PISA report said the Covid-19 pandemic was partly to blame for the poor results.
"No change in the OECD average over consecutive PISA assessments up to 2018 has ever exceeded four points in mathematics and five points in reading: in PISA 2022, however, the OECD average dropped by almost 15 points in mathematics and about 10 score points in reading compared to PISA 2018. Mean performance in science, however, remained stable. The unprecedented drops in mathematics and reading point to the shock effect of Covid-19 on most countries," the PISA report said.
However, it said for some countries other factors were at play.
"In reading, for example, many countries such as Finland, Iceland, the Netherlands, the Slovak Republic and Sweden have seen students scoring lower marks for some time - in some cases for a decade or more. Educational trajectories were negative well before the pandemic hit. This indicates that long term issues in education systems are also to blame for the drop in performance. It is not just about Covid," the report said.
New Zealand's scores were above the OECD averages in all three subjects, though only just so for maths.
Considering all 81 participants, this country ranked 10th in reading, 11th in science and 23rd in maths.
The Ministry of Education said New Zealand could be ranked lower considering the likely bias in its results, but so too could other countries with likely upward bias due to low participation. Those countries included the United Kingdom, Scotland, and Ireland.
Singapore had the highest average scores in all three subjects.
New Zealand's results showed a decrease in high performers and an increase in low performers over the past 20 years in all three subjects.
The effect was strongest in maths where the percentage of low performers increased from 15 percent of New Zealand 15-year-olds in 2003 to 29 percent in 2022 while the percentage of high performers dropped from 21 to 10 percent in the same period.
What is PISA?
The Programme for International Student Assessment has run every three years since 2000.
About 4700 New Zealand 15-year-olds from 169 schools sat the tests in term three last year.
Internationally, 690,000 students took the assessment.
Each student sat tests in two of the three subjects, with each test lasting about one hour.
The tests were a mixture of multiple-choice questions and questions requiring students to construct their own responses. Students also answered a background questionnaire, which took about 35 minutes to complete.
For the 37 OECD nations that participated, the average scores in PISA 2022 were 476 in reading, 485 for science and 472 in maths - the lowest figures recorded. Twenty points was regarded as equivalent to year of learning for 15-year-olds.