• They make a big impact: Even if you don't believe in education league tables, they make things change around them. The Programme for International Student Assessment tests run by the Organisation for Economic Co-operation and Development have been seen as driving education policy and stirring education ministers to measure themselves against international standards.
  • You rank only what you can measure: It's no coincidence that global rankings focus on maths, science, and reading. They are much more straightforward to test and mark than more complicated, culturally defined subjects such as history or literature. But does that mean that less value is attached to subjects that won't see countries climbing up league tables?
  • Are they fair? It might seem one-sided to compare a wealthy European school system with a developing country, or a huge sprawling country with a compact city-state. But the argument of league tables is that it doesn't matter whether it's fair - it's the reality of a globalized world.

Read the full article on global school rankings by Sean Coughlan at BBC