Parents and teachers are to get tougher guidelines on helping pupils with their coursework, in a bid to curb cheating.
The report demands greater consistency across exam boards
Education Secretary Ruth Kelly has called for an urgent review of the use of coursework in GCSE subjects.
This follows a report from the QCA exam watchdog that pupils have been copying each others' work and downloading essays from the internet.
The report says some parents and teachers are effectively doing children's coursework for them.
There can be so much assistance that it results in "cloning" of coursework, says the QCA report - and it warns that copying essays from the internet "cannot be controlled".
Its report said there was clear agreement that things such as extended essays, projects, practical work and performances were valuable.
written work and extended essays
project work and investigations
works of art or other items
individual or group performances
statistical and numerical tasks
Ms Kelly said coursework should be used only where it was the most appropriate assessment method.
"Parents quite properly want to play an active part in their children's education," she said.
"I am therefore particularly concerned that they are given clear guidance on what is or is not permissible as soon as possible."
The consultation has been carried out by the qualifications regulators, headed by the Qualifications and Curriculum Authority (QCA) in England.
It found that coursework could help to motivate candidates, and provide rich opportunities for in-depth study and taking responsibility for their own learning, it said.
Coursework is marked internally within schools, while exam boards call in samples of the work for external checks, known as "moderation".
At GCSE level, it varies from 20% of the overall qualification in double science, maths and religious studies, to 60% in art and design and design and technology.
At A-level it can be from nothing to 30%, or 60% in the case of art and design.
Concerns centred on ensuring the work was the candidates' own.
The rules on how much teachers could help were "limited and open to interpretation".
In some cases so much was given in the form of writing frames, templates and checklists the report said it amounted to "coursework cloning" with little original work.
There was a similar range of help from parents, guardians, siblings and friends.
A Mori survey of parents had indicated that 63% helped in some way with GCSE coursework - with 5% actually drafting some of it.
The report said: "The availability of the internet is a powerful aid to learning but carries a new generation of risks of plagiarism."
SURVEY OF 400 PARENTS
63% helped with GCSE coursework in some way
50% occasional advice
39% helped find information
37% checked spelling or grammar
26% supervised the work
5% drafted some of it
most help was with mathematics
Assignments were available from at least 10 popular websites at any level and in any subject, either free or custom-made and for sale, and "cannot be controlled".
Professor Jean Underwood, of Nottingham Trent University, is being asked to provide technical advice on detecting this.
But collusion with friends was a bigger problem. Teachers often encouraged team work so it was not surprising friends helped one another.
Teachers varied in the value they put on coursework.
Almost all the history teachers surveyed felt it was an important, integral part of the course. In contrast, 66% of maths teachers indicated it was sometimes problematic.
Science teachers regarded coursework as "jumping through hoops" to maximise marks and "a poor educational tool".
The report also identified various approaches to marking and to moderation.
Exam boards are being told to take action to address all the issues, in time for the 2006 summer exams.
The Secondary Heads Association said the report strengthened its argument for a system of "chartered assessors" - experienced practitioners accredited to carry out assessment within schools.
Conservative education spokesman, Mark Hoban, said that the education secretary "should not need yet another review to tell her that the increasing reliance on coursework is leading to more cheating and undermining standards".
The report - A review of GCE and GCSE coursework arrangements - involved canvassing over 1,700 teachers' views, and in-depth interviews with over 460 candidates and more than 400 parents.