Academics at the London School of Economics (LSE) said that while the Scottish system remains on a par with those elsewhere in the UK, it has not progressed at the same rate as the English system since 1999.
The report, Education in a Devolved Scotland: A Quantitative Analysis, said the rate of change north of the Border had been “very stable”, while increasing in England during the same period.
The study compared exam results as well as the performance of each country in international comparison exercises.
The authors of the report note that the performance of the education system is one of the questions that voters may consider in the run-up to next year’s independence referendum.
Written by Stephen Machin and Sandra McNally, of LSE’s Centre for Economic Performance, the report states: “Our analysis of national statistics showed that Scotland’s performance has been very stable over time whilst, in contrast, England’s performance has been increasing.”
It adds: “Our analysis of international test scores showed Scotland in a favourable light internationally and, while there were some inconsistencies in findings depending on the survey studied, they tended to show Scottish pupils performing as well as, if not better than, other pupils in the UK on these measures.
“However, we found no evidence of any improvements in Scotland in any of the tests over time – backed up by very stable performance in national assessments. Furthermore, our findings also showed deep levels of inequality in Scotland, particularly between pupils from different socio-economic groups.”
While comparing the differences between the education systems, the report also notes that tax and benefit policies are decided at a UK level, limiting the extent to which each is “truly devolved”.
Scotland’s inability to raise taxes or alter other aspects of fiscal policy limits the level and distribution of spending on education, the report notes.
Professor David Raffe, of the Centre for Educational Sociology at Edinburgh University, said: “It’s fair to say education has not improved greatly [since devolution]. Devolution has not made a difference to the rate of progress.
“Curriculum for Excellence is creating a divergence between the English and Scottish systems, and that does mean that in ten years’ time, the types of learning could potentially look a bit more different. But it’s going to take some time before the changes filter through.”
A Scottish Government spokesman said: “While outcomes are improving for most people in Scotland, they are not improving fast enough for the most disadvantaged in our society.
“The continuing implementation of Curriculum for Excellence will help Scotland maintain and improve our excellent standards in education.”