Every three years, a new round of Pisa scores is released into the world. While many question whether the Programme of International Student Assessment should have the level of influence that it does and how reliable the data is, there is no doubt that the results influence government policy. And when things go badly, that they become ammunition to use against governments.
Yesterday was Pisa day. Beforehand, the big question in Scotland was whether the downward trajectory of recent years would continue. The answer? Follow the links below to see how Pisa day unfolded in Scotland.
At 8am, the results were released en masse – and the initial picture looked mixed for Scotland. It wasn't long before the government take emerged. Needless to say, its analysis did not match that of its political rivals.
Pisa results: No sign of closing-the-gap cash making an impact
Pisa: Are the Scottish and English education systems less different than we thought?
Pisa in Scotland: 2018 results reveal a mixed picture
There was also some eye-catching data about teachers who work in schools in disadvantaged areas, and on that most topical of issues in Scotland – the attainment gap.
There was some tough analysis from Professor Lindsay Paterson, but also some cheering news about how pupils in Scotland view their teachers.
Finally, Professor Mark Priestley shared his insight into where we are with Curriculum for Excellence, and why we should be wary of drawing a direct line between the state of CfE and Scotland's performance in Pisa.
That was it for our coverage of Pisa day – but if we've learned anything from previous years, like it or not, the ramifications will be felt for some time to come.