At Oxford Home Schooling, we have supported students following a wide range of GCSE and (latterly) IGCSE courses for more than 30 years, and we have no vested interest in either system. But there is no evidence that GCSEs are harder (Letters, 28 August). Where the specifications are not interchangeable (as they often are), the exam boards have done everything they can to make them equally difficult and to ensure that a grade 7, for example, in one is comparable to a grade 7 in the other. Nor is there any evidence that private schools and their students are motivated by the chance to do coursework, or that that would give them an advantage. In fact a high proportion of IGCSE candidates follow the non-coursework option. IGCSEs gained a footing in the UK 10 to 15 years ago precisely because they offered a chance to gain qualifications without the need for non-exam assessment (coursework). Their continued use by UK private schools and, indeed, Oxford Home Schooling, is as much a consequence of inertia as anything else. There are many reasons to be sceptical about the UK’s private schools, but this is not one of them. Dr Nick Smith Principal, Oxford Home Schooling