During my years as a UK school leader, I’ve seen how education is becoming increasingly data-driven. We have inspections, reports, league tables, audits and internal data constantly flowing within schools. It can feel at times as if we are to be consumed by data. However, good teachers are constantly striving to improve, and they know that it is reliable data which is often key to improvement. Without data we have no proper sense of how we are doing now, and without an objective assessment of how things are, planning future improvements can be wasted.