That is the view of the latest analysis of exam results carried out by the right-wing Policy Institute, which says they give "considerable cause for concern".
It confines its number-crunching to the proportion of pupils in fourth year in Scotland and England, who achieve five "good grades" in external exams, including maths and English.
In 2006-07, according to the institute, 39.2 per cent achieved that benchmark in Scotland, compared with 43.8 per cent the previous year. In England, the figure rose to 45.7 per cent from 45.3 per cent - putting its schools ahead of their Scottish counterparts.
The institute, which was set up by broadcaster and former Scotsman editor Andrew Neil, defines "good grades" as Standard grade 1-3, Intermediate 2 A-C or Intermediate 1 A in Scotland, and GCSE A*-C in England.
The Scottish picture on those definitions is one of steady decline in performance since devolution when Scottish pupils were at 50 per cent on the "five good grades" test, 10 points ahead of England where the picture is one of steady improvement over that period.
The institute's figures build on a report it commissioned from James Stanfield of the School of Education at the University of Newcastle, who published his findings in March, under the title of How Good Are Scotland's Schools? The updated report acknowledges that Scotland and England have different school systems and different systems of measurement, and that one year's results cannot be regarded as a trend.
But, it adds: "Nonetheless, these figures are the best we have. They are not the result of a small survey, but the accumulated data of many thousands of actual exams taken by real pupils. They are widely considered to be robust, especially in the recording of comparative performance over time. They seem no more likely to underplay performance than overplay it."
The decline in Standard grade performance comes against a background of ever-increasing expenditure on education north of the border which, the institute calculates, has risen by 93 per cent per pupil since 1999.
In his original report, Mr Stanfield acknowledged that Scottish pupils had performed well in some international surveys, but they also did badly in others. At best, he says, they reveal "a mixed bag" of results and do not support claims by former ministers that our education system is "among the best performing in the world".