The explanation for the widespread perception that standards at GCSE and A-level are falling may be that pupils need much wider knowledge for exams in the Nineties than they did in the Seventies.
As a result, the report is believed to suggest, standards in some traditional skills in maths have declined though those in new areas such as statistics are improving. Views about what pupils should learn have also changed, so that exams put more emphasis on understanding and less on learning facts.
The inquiry, set up by Gillian Shephard, the Secretary of State for Education, has caused a row between the Office for Standards in Education (Ofsted) and the School Curriculum and Assessment Authority which conducted it.
Chris Woodhead, the Chief Inspector of Schools and head of Ofsted, is understood to share the traditionalists' view that there is evidence that standards are falling. Sir Ron Dearing, the authority's head, and his officials are thought to believe that the report gives a fair picture.
The inquiry team, which emphasises the difficulty of drawing firm conclusions on the available evidence, looked at syllabuses, papers, exam scripts and mark schemes in English, maths and chemistry since 1975 when the old 0-level exam was still in place.
Only in maths did they find any evidence that exams might be getting a little easier.
At A-level, pure maths appears to be less demanding and there is less emphasis on algebra, problem-solving and reasoning though mechanics standards remain the same and those in statistics are getting better.
At GCSE, they found maths exams are as hard as they were in the Seventies for most students, though the best candidates are not doing as well in some topics, for example, algebra.
The draft points out that there have been big changes in the maths syllabuses for both exams so that students are now expected to carry out a much wider range of operations.
In English A-level, there has been no change, the report suggests, and in chemistry the differences are small: current exams put less emphasis on learning facts and more on understanding.
English GCSE syllabuses have become harder since 1975, the inquiry concludes, but information about standards is limited. The available evidence suggests that it is no easier now than 20 years ago to get one of the top three grades, A - C.
In chemistry, too, students need to know more than they did in 1975 and there has been a shift away from learning facts to applying knowledge. The introduction of double science may have led to a decline in knowledge about basic concepts.
The report, due to be published before Christmas, is unlikely to settle the standards dispute which is fuelled each year by rising pass-rates at both GCSE and A-level.
The team found that the evidence was limited because the exam boards could not produce scripts for the Seventies, though a few had some from the Eighties.Reuse content