Secondary school league tables: What's changed?

Robert Cuffe, BBC News head of statistics, explains how new-style secondary school league tables for England work.

Schools which took in high-flying children did well under the old system, whereas now the numbers use a “value added measure”, he says.

"This measure is telling you, roughly, if I took my kid and put them in this school, how many grades would they get on average better than if I put them in a different school," he says.