Marks out of 10 should be the exception rather than the rule. Brief remarks such as "could do better" and "satisfactory" should also be outlawed and replaced by detailed comments on how pupils can improve.
Competition and marking which compares pupils, such as gold stars or ranking, should also be abandoned because they make the least able give up. King's College researchers who reviewed the effect of teachers' assessment of 10,000 pupils from all over the world during the past decade found marking or "feedback" is more important than almost anything else in determining progress.
The study shows pupils who have the same teachers progress if they receive comments on their work but not if they receive only marks or even marks and comments.
Explanations of how pupils could improve and what they need to learn next could raise standards by as much as two GCSE grades in each subject over the country.
Professor Paul Black, one of the researchers and architect of the proposals for the first national tests 10 years ago, said the present government tests, targets and league tables might be counter-productive.
Tests and targets do not in themselves raise standards, the study argues, and ministers need to focus on how children are assessed in the classroom. Dr Dylan Wiliam, head of the King's College school of education, denied their views meant a return to the progressive notions of the sixties.
Teachers would find it harder to give pupils a clear idea of how they could improve than to tick a pile of books.
They were not against national tests or giving pupils marks or grades once a term or once a year.
"But the place of marks needs to change. Too much emphasis on marks means pupils who are finding it difficult tend to give up."
The effect on able students could be equally unhelpful, he said.
Because they nearly always received high marks, they sometimes coasted. "I once gave the cleverest kid in the class E for effort. His parents were not happy." Earlier this week, Chris Woodhead, chief inspector of schools, said marking was not tough enough in some schools and teachers were not using assessment results to raise standards.
Dave Anderson, head teacher of St Chad's Secondary School in Essex, who supported the findings, said he knew he had not always marked work as well as he should.
"I remember timing with colleagues how quickly we could get through a set of book. We focused on `well done' or `good effort' without ever explaining why it was good."
Prof Black said the change of direction called for in the study would not mean longer hours for overloaded teachers. "This is about working smarter, not working harder."
Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers, said: "I'm just pulling myself down from the ceiling. These people need to try out some of these crazy ideas in the classroom. Teachers would spend all their time assessing instead of teaching. Marks out of ten and percentages produce a much clearer picture for pupils and parents."Reuse content