The first question that should be asked about any major change to the education system is a simple one: how will this help the bottom half of pupils in our schools?
This is not about silly maths: complaints that "half our children are below average" and "only one in 10 is in the top 10 per cent". The proportion we now regard as failing to meet the expected standards at GCSE is about half. This echoes the situation in 1963 when a government report warned that it was vital for the country that more attention was given to the bottom half of students, a group it dubbed "half our future".
So how will the new exam system announced by Michael Gove this week help those pupils?
On the upside, the English Baccalaureate Certificates (EBCs) are not the return to the two-tier system of ^O levels and CSEs that some had feared (pages 8-9). Indeed, from one angle, they could seem more progressive than GCSEs, as there is no risk of pupils being consigned to foundation papers that prevent them from gaining As and Bs.
But the main difference ministers have emphasised is that the exams will be tougher. The minimum standard will be harder than a current C, a wider range of grades will exist, structural crutches like modules will be taken away and the difficulty level will be matched to some of the world's most challenging tests.
This may be stimulating for high-achieving pupils who find GCSEs yawn-worthy. But how does a harder set of exams at 16 help the students who are failing the ones that exist already?
Our brightest 16-year-olds could be stretched to PhD level and it would have bugger all impact on our standing in international league tables. Those pupils are not the ones failing the Pisa (Programme for International Student Assessment) tests.
Yes, high aspirations are vital, as has been proven by those schools fighting successfully to break the link between children's backgrounds and attainment. Yet simply raising the bar does not automatically raise results. At every other education conference a teacher will stand up to repeat the folksy cliche "You can't fatten a pig by weighing it". It is oft-repeated because it is true.
The other problem is that while the new exams may not present a two-tier system for ability, they will worsen the two-tier divide we have for subjects. The EBac subjects will not just have precedence in league tables, they will have separate, higher-status exams with different grades. And if a pupils prefers art, design and technology, music or computing - the subjects at the heart of Britain's creative industries - tough. They must keep trying for the EBac, at 17 and 18, because Latin and geography apparently matter more.
England should be looking to create more Jonathan Ives - the design guru behind, among other inventions, the iPhone. The latest model of that gadget has been predicted by economists to see such humongous sales that it will add half a percentage point to the GDP growth of the US. Sir Jonathan has credited his success to his DT teacher father and his "very British design education".
But instead we have been offered an exam system geared towards creating more Michael Goves, and which may fail to support the pupils who are half our future.