It is the week that thousands of teenagers have been looking forward to yet dreading ever since they finished their exams.

This Thursday, A-level students will discover whether they have got the grades they need to go on to university, or progress with other plans.

And the following Thursday, thousands of GCSE pupils will learn the outcome of years of hard work and study at school.

Recent years have been a time of rapid change for the education system in England, and some of these reforms will change the way that the performance of schools and colleges are judged this year.

The difference will be most noticeable at GCSE level, where the familiar measure of how many pupils gained at least five GCSEs at A* to C, including English and maths, which has often been described as the government's 'gold standard', has been consigned to the history books.

There have long been concerns that this measure encouraged schools to concentrate on pupils on the C/D border line to improve their league table positions, at the expense of pupils expected to get higher or lower grades.

From this year onwards, league tables will now compare schools using a new measure, Progress 8, which attempts to show how much progress pupils have made between the end of primary school and their GCSEs.

For pupils themselves, it is still their individual exam results that matter, but for schools, Progress 8 is what will be used to judge their success.

Because Progress 8 is calculated by comparing how children compare to other children across the country, we will not know any school's Progress 8 score for 2016 until the results across the country have been collected, and averages calculated.

The government will publish these figures later.

Instead, on GCSE results day, schools will report a different measure - the percentage of pupils who gained an A*-C in both their English and maths GCSEs.

But if you think this year will be the end of exam upheaval, you will be disappointed.

Next year, students will not receive their GCSE grade in the form of a letter, such as A, B or C, for English language, English literature or maths.

Instead, they will receive a numbered grade, from one to nine, with nine the highest. Other subjects will follow in later years.