The report for the centre-right Social Market Foundation, by the academic John Marks, analysed test results at ages seven, 11 and 14. It contrasted performance with the levels expected of an average child at each age, and calculated the spread of children's "educational" age compared to their chronological years.
At age seven, Mr Marks concluded, children were on average slightly ahead of national expectations. But at age 11 they were about a year behind, and at age 14, the average child was two years behind expected standards.
Commenting on the results of his analysis, Mr Marks, formerly a member of the Schools Curriculum and Assessment Authority - now the Qualifications and Curriculum Agency - said: "It has taken over a decade for data for individual schools derived from national curriculum tests to become available at ages seven, 11 and 14.
"Given the disastrous national situation that this data has now revealed, it is perhaps not surprising that so many teachers' organisations and others ... were so reluctant to agree to tests taking place at all."
The conclusions of the research were disputed, however, by Ted Wragg, professor of education, at Exeter University, who said: "It is indisputable that variation in children's performance increases with age. It would be astonishing if it were otherwise."
It was also "nonsense", he said, to suggest that all children should reach the level of achievement expected of the average.
"If no drivers passed the driving test, you wouldn't conclude that all drivers were poor drivers - you would conclude that there was something wrong with the test," he said.
The "school run" may be jeopardising children's health in later life, according to a study by the Institute of Child Health, also published today.
A survey commissioned by the Pedestrians' Association found that 59 per cent of children aged between five and ten walk to school, compared to 72 per cent in the mid-1970s.
The report - "The School Run - Blessing or Blight?" - warned that health problems such as obesity, heart disease and hip fractures may increase unless this decline is reversed.
Dr Ian Roberts, of the institute, said: "Parents drive their children to school to protect them from danger, but they are increasing the risks of obesity and dependency and establishing behaviour that will undermine their children's health in later years."Reuse content