I kind of feel peoples' heads might explode if they knew that we set results via an algorithm every year. Usually it has more and better data in it. It's still an algorithm. https://twitter.com/mikercameron/status/1294736229729218560

Every year results are checked against previous years results using a process called "Comparable Outcomes" and grade boundaries are set accordingly. Performance of previous cohorts and prior attainment is always taken into account so as to avoid grade inflation.

I think most people assume that GCSE and A-Level exams are criterion-referenced (e.g. based on meeting a given set of criteria regardless of what other students do). But they're referenced against historic performance and prior attainment (except in rare circumstances).

As @JohnPeterJerrim notes we also now have a National Reference Test as a separate check as to whether there is genuine improvement that would justify grades going up. (One of the few useful things I managed to make happen when at DfE). https://twitter.com/JohnPeterJerrim/status/1295038740226871298?s=19