Today it seems that every aspect of teaching must be quantified, measured and audited, as the professional judgement and autonomy of the teacher is subordinated to data and tables. Where once exams were seen as an aid to tracking students’ grasp of subject knowledge, critics argue that this traditional function is ‘old hat’ compared to perpetual monitoring of pupil performance. Does this ‘data revolution’ make for more transparency, or does it push more and more teachers to be a slave to the data? Filmed at the Battle of Ideas, this discussion considers where learning fits in.