Mark Lehain is Director of the Campaign for Common Sense, and the founder and former Principal of Bedford Free School.

In spite of the impression that the media may have given at the time, the exam mess this summer wasn’t unique to the UK – many other countries struggled to agree on what to do. This isn’t surprising as there are lots of different views on what qualifications are for and how best to award them.

So we can perhaps forgive making it up on the hoof this year, but there is no excuse for being like that in 2021. Giving advance notice of how things will work next summer is one of the most important steps politicians can take to make the whole situation less daunting.

However, making the right kind of decision is even more important. This is why today’s announcement by Gavin Williamson about exams going ahead in England is such good news for pupils, and why the choices made in Scotland and Wales are so disappointing.

Amid the Covid chaos, it’s vital we remember the reason why the UK has the kind of exam systems that it does. Bear with me for a minute, as it’s a bit geeky – but super important. Sadly it seems to have been forgotten by some nationalist politicians, and it’s the poorest kids who are going to get hurt the hardest as a result.

There are loads of different ways of testing people. No form of assessment is perfect. Whether we use teacher grades, interviews, open book tests, unseen exams, portfolios – they all have strengths and some major drawbacks.

Over time, though, we have come to understand that for the UK’s school systems standardised national assessments are the best and fairest way to measure what pupils have learnt, and how different schools or groups of pupils are performing.

This means we want our assessments to be as accurate as possible – that is to say, we want them to be the best reflection of what pupils know and can do. And for this, we need them to be as valid and reliable as possible.

By valid we mean the assessment actually measures the thing we want to know about, not something else. And by reliable we mean that it measures it consistently, so that the same pupil would get the same result over time, or two pupils with the same knowledge would get the same result as each other.

The big advantage that national standardised exams have is that we can make them more valid and more reliable than any other method of assessment. This is why sticking with exams as far as possible for 2021 is so important. It is a question of fairness.

With this in mind, the measures announced today for England’s GCSEs and A-levels are sensible moves to address the uncertainty and unavoidable disparities that Covid has created for schools and pupils.

As well as delaying exams to provide more teaching time, giving advance notice of some of the topics that will be covered will help kids that have missed more lessons and are struggling to catch up in time. Allowing more exam aids, like formulae sheets, will reduce the memorisation pressure for some. Having a set of additional exams as backup for pupils who miss the main papers due to illness or self-isolation is a simple but very reassuring measure that also maintains accuracy of assessment.

Even allowing some grade inflation like that we had this summer feels reasonable now – think of it as a sort of Quantitative Easing for exams: not ideal, but a necessary evil for now to get through things.

Overall then, next summer I think England’s 16 and 18 year olds will get the best deal possible given the unprecedented circumstances they’ll have been through.

But boy do I feel for pupils and teachers in Scotland and Wales, where politicians have abandoned exams and moved to teacher-assessment and other approaches. Not only are these much less valid and reliable, they’ll cause more interruptions to school life across the academic year, and create even more work for hard-pressed teachers already dealing with Covid disruptions.

However, we are where we are, and at least everyone knows what is going to happen. Now we need to get behind teachers, pupils, and their families, and support them through the rest of the academic year. High-stakes qualifications are stressful enough at the best of times, but in 2021 they’re going to be even more so, whatever steps are taken to mitigate things.

Hopefully by the time next summer’s results are awarded, life will be largely back to normal and we can get back to business-as-usual: bickering over discipline in schools, or why girls do better than boys. Bring it on!