By Leigh Thomas
PARIS (Reuters) - Education performance has largely stagnated in many OECD countries over the last two decades despite higher spending, the Organisation for Economic Cooperation and Development said on Tuesday in a survey of international learning standards.
The survey by the club of 36 mostly advanced countries did not spell out the reasons for the lack of improvement.
But in the past the OECD has suggested improving teacher performance is more important to the quality of learning than other factors like spending more to reduce class sizes.
Students' average performance in reading, mathematics and science was largely stable in OECD countries, according to the results of the global education test, held every three years.
The Paris-based policy's forum said it was "disappointing" there had been practically no improvement in OECD countries performance since it started the Programme for International Student Assessment (PISA) in 2000.
It was all the more galling in light of the fact that per student spending in OECD member countries had risen more than 15% over the past decade, the organization said in a report presenting the study.
About 600,000 15-year-olds in 79 countries and economies took the two-hour test last year for the latest study, which is closely watched by policymakers as the largest international comparison of education performance.
As OECD countries stagnated, students from areas surveyed in non-OECD member China -- Beijing, Shanghai, Jiangsu and Zhejiang -- and in Singapore once again outperformed peers from all other countries in reading, mathematics and science.
Out of the 79 countries, only Albania, Colombia, Macao, Moldova, Peru, Portugal and Qatar had seen an improvement in their scores since joining in PISA, and only Portugal is a member of the OECD.
While important, funding was not everything, as demonstrated by the case of Estonia, which was one of the top scoring OECD countries despite education spending 30% below the OECD average.
Australia, Finland, Iceland, Korea, the Netherlands, New Zealand and Slovakia have all seen their average performances in reading, mathematics and science decline since participating in PISA.
With reading the main focus of the test this time around, it found that one out of four students in OECD countries could not complete basic reading tasks, leaving them dangerously ill-prepared for a life in an increasingly digitalized economy.
Students' social and economic background remained a leading factor for success at school, with the richest 10% of students in OECD countries reading at a level three years ahead of the poorest 10%.
However, the link between background and performance was weakest in Australia, Canada, Denmark, Estonia, Finland, Japan, Korea, Norway and the United Kingdom, which meant their education systems were fairer, the OECD said.
Screen time was found to be increasingly eating into students reading outside of school in the 79 countries surveyed. Time reported online was nearly three hours per workday, up from less than two in 2012.