The advanced Extension exams being developed for bright sixth-formers will be very tough.
Ministers hope to peg the new qualification to standards abroad making comparisons easier than with the very specialised A-level.
Methods of assessing 18-year-old school-leavers vary greatly around the world. But in most countries, they are based on a far broader and more detailed account of the student's performance than is provided by A-level.
In France, the passport to higher education is the "baccalaureat". Students are examined in a range of subjects varying according to the type of bac they choose but always including French, maths and foreign languages. They must score at least 360 out of a possible 720 marks to pass and those who do well get access to the better faculties.
Many of the brightest and most ambitious want to get into the prestigious and super-selective "grandes ecoles". This usually requires a further two years of study leading to a competitive exam. To be accepted students have to send in a dossier including their school record and reports for the previous two years.
Entry to university in Germany depends on passing the "abitur", which tests students' performance in up to 11 subjects. Marks are based on classwork and tests in the last two years at school as well as final written and oral exams. To get on to a popular course like medicine in a good faculty students might have to score 15 in three subjects and very highly in all others.
In the United States colleges and universities pay as much attention to applicants' scores in standardised tests as to high-school records. The oldest of these tests, taken annually by more than 1 million students, is the Scholastic Assessment Test, which aims to test aptitude rather than achievement. It is divided into two sections, maths and verbal, each marked out of 800.
Candidates wanting to gain entry to an Ivy League university would usually need to get marks well into the 700s in each.