Academics at the Institute of Education in London are warning ministers that even if the national targets for literacy and numeracy set for the year 2002 are met it will not necessarily prove that standards among 11-year-olds have risen.
The reservations expressed in the paper about the Government's key objective of ensuring that 80 per cent of 11-year-olds achieve a particular level in English and 75 per cent do so in maths will be seen as significant because they are made by specialists on research into the effectiveness of schools.
It will also be embarrassing because these caveats comes from the institution which formerly employed Michael Barber, now head of the Department for Education and Employment's standards and effectiveness unit.
The response from the institute to the Government's White Paper on education says that research shows it is impossible to define consistent standards for 11-year-olds in maths and English over such a period.
It points out that the Government wants to be judged against its success in achieving its targets for 11-year-olds' performance at level 4 of the national curriculum, but decades of research show there is no authentic way of measuring progress over time.
The paper says "it is impossible to distinguish 'real' changes in the performance of pupils from changes in the (different) tests or examinations that are used".
It continues: "The only possible way to ensure that the same thing is being measured is to use precisely the same test in precisely the same way over time. This, of course, would be unacceptable, so the conclusion must be there is literally no way in which level 4 (in 1996 or 1997) could be maintained as a standard through to 2002."
The technical problems posed by the Government's pledge that it will be able to demonstrate an improvement in standards during its first term are dealt with in detail. This section of the paper concludes: "The problem with which the White Paper has to engage is that there exists no authentic way of measuring what is happening in the way that is being inadvertently suggested."
The institute is keen to ensure that the views expressed in the response are not interpreted as an attack on Government policy.
The paper was "offered in the spirit of constructive criticism from an institution which cares deeply about quality and which recognises the need for change".
Professor Toni Griffiths, dean of new initiatives, adds: "If so much emphasis is being placed on comparisons, then very great care has to be taken in the way data are interpreted."
A Department for Education and Employment spokesman said the institute's suggestion that targets might not be met because of the testing arrangements was "utterly absurd and farcical".
"We have to live in the real world and in the real world we cannot have the same tests every year. The way to maintain rigour and quality is to have constant monitoring which is what the Qualifications and Curriculum Authority is doing," he said. " If the institute's case was taken up we would have to do away with all testing including GCSEs and A-levels."