Scotland's struggles in maths and science are nothing new, but researchers are stressing their importance ahead of the first new set of data in over five years.

A new report analyses Scottish pupils’ performance on Programme for International Student Assessment (PISA) tests since 2006.

The PISA tests – administered by the Organisation for Economic Co-operation and Development (OECD) – assess 15-year-olds in reading, maths and science.

There was a gap in testing between 2018 and 2022. Results of the 2022 session are due next month and will represent the first measurement in the aftermath of the Covid-19 pandemic.

Researchers from The Institute for Fiscal Studies (IFS) highlighted a trend of declining performance –from “high” to “average” – among Scottish pupils in maths and science since 2006.

The report also found significant performance gaps between pupils in the top and bottom socio-economic rankings. In science, the gap is the same as the one that separates the UK from Colombia (91 points).

The performance gap is slightly mitigated by findings that Scotland tracks with most of the 79 other PISA participants around the world.

But there is another silver lining in the results, researchers have said: On a one-off Global Competence test in 2018, Scotland outperformed most other countries and beat the overall average by almost 50 points.

Andrew McKendrick, research economist at IFS and co-author of the report, said this has interesting implications for the Curriculum for Excellence (CfE), though there isn’t enough data for it to serve as a direct assessment.

"The Global Competence test in 2018 was aimed at trying to understand how the education systems in different countries perform in terms of producing globally-informed citizens.

“Scotland's success on this test is interesting because it gets close to measuring what the Curriculum for Excellence is trying to engender in Scotland's students."

READ MORE: Scotland to rejoin international education league tables

Overall, however, Ms McKendrick called the findings “disappointing” for Scotland.

“Scotland has gone from a position of high performer to an average performer.

“The gap between rich and poor is slightly narrower than in England, but only because richer Scottish pupils score lower than their English counterparts.

“Large increases in spending and big reforms, such as the Curriculum for Excellence, do not seem to have translated into higher performance in these core subjects.”

He added that highlighting the historical trends ahead of the release of the 2022 results should help contextualise any new data. The results are nothing new, and concerns over Scotland’s growing attainment gap between richer and poorer pupils and declining global position in maths and science are well-documented.

But Mr McKendrick said that taking a longer view will hopefully keep underlying issues from slipping through the cracks.

"It is essential to have a baseline for the new data due next month.

“A lot has happened in the intervening years, including the Covid-19 pandemic, and it will be important for decision-makers to know if these disruptions are an accurate explanation of Scotland's performance in the latest tests, or if there are longer-standing trends at work."

READ MORE: Scotland's Curriculum for Excellence 'to blame' for lower maths and science scores

From 2006 to 2012, PISA data shows that Scottish pupils regularly outperformed the OECD average. During this time, Scotland also topped UK rankings in maths and reading most years.

But that performance has dipped since 2012. IFS data shows that, since 2006, Scotland’s average PISA scores have fallen from 17 points above to OECD average to six points above. In the same period, Scotland also went from being the top-performing UK country to falling below England and Northern Ireland.

A Scottish Government spokesperson said that Scottish education has changed much since the 2018 PISA results. Other factors, such as SQA attainment and teacher-pupil ratios open the door for a more optimistic view once the 2022 PISA data is released.

“The data in this report is now five years old and predates the pandemic. This year’s exam results showed the overall pass rate for National 5, Highers and Advanced Highers is up from the pre-pandemic level, including increases in the pass rates for Higher Maths, Biology, Chemistry and Physics.

“We have recently seen the biggest ever reduction in the attainment gap on literacy and numeracy in primary schools in a single year and we are seeing record proportions of school leavers going on to positive destinations including work, training or further study.

"Scotland has the most teachers-per-pupil compared to the rest of the UK, and education spend per person is higher than England and Wales.”