GCSES provide pupil motivation, let teachers and pupils know what is required, bestow status on the whole educational endeavour, encourage quality and provide an objective means of judging the success of the nation's educational system.
These, according to Jeremy Tafler, educational policy adviser to Edexcel, are some of the key arguments in favour of retaining the examination.
"Essentially the important thing about GCSEs is that they do not just measure attainment," he says, "but they encourage it. They provide motivation through having interesting courses that teachers want to teach and that kids want to do."
In support of his case, Mr Tafler quotes Michael Barber on the GCSE from his book The Learning Game. Professor Barber, who conducted research on pupil motivation at Keele University, said: "Only in year 11, the GCSE year, does the (motivation) curve begin to rise again. Here, while parental support has continued to fall, there is some evidence of more positive attitude and improvedmotivation.
"It seems that as the examinations at 16-plus loom, large numbers of young people begin to buckle down and the adrenalin - at least a little - begins to flow."
And: "Examinations at 16 should cease to be - as they still are, both in design and in cultural impact - a school-leaving examination, and become instead a staging post on the route to lifetimelearning."
Second, Mr Tafler says, GCSEs let teachers and pupils know precisely what knowledge, understanding and skills are required.
Third, they bestow status on the educational enterprise. "The British, " he says, "have not always valued learning for itself as much as some other nationalities have done. There is evidence that we are beginning to turn this around, but it is public examinations such as the GCSE that confer credibility. A GCSE is seen to be a legitimate course: pupils, teachers, parents and employers know that what is being studied is of reputable quality and relevance."
Fourth, the GCSE encourages quality. "The awarding bodies continually strive to offer ever more appropriate, more interesting, more innovative and more motivating syllabuses, better course support, more feedback and more service, because if they do not, people are not going to go and buy their exams.
"Lastly, the GCSE is a reliable method of judging not only students but also schools, local educational authorities and the entire national system.
"League tables make the testing high stakes, so what is tested will end up being taught. The examinations need to be comprehensive and valid. It is not only a case of valuing what is assessed but making sure that we assess what is valuable. If you are going to find out how well you are doing as an educational system, you do have to have something external by which to judge it."