Very appropriately, last week’s front cover featured a headless statue accompanying the headline “Missing something? Why the Pisa league tables could be faulty” (26 July).

It reminded me that in the 19th century there were a large number of international phrenological studies that attempted to correlate precise head measurements with the mental faculties of races and peoples in different countries. Despite the accuracy of the measurements (to the nearest millimetre or fraction of an inch), the findings were later shown to be spurious and the supposed “science” totally discredited. But 150 years on, Pisa-type measurement is a form of international educational phrenology. It too will be discredited. Perhaps, in your feature, we are seeing the early signs of its educational decapitation.

Colin Richards, Spark Bridge, Cumbria.