A paper published last week in an academic journal called npj Science of Learning attracted an unusual amount of press attention. It looked at the GCSE results of 4,814 students at three different types of school — comprehensives, private schools and grammars — and found that once you factor in IQ, prior attainment, parental socio-economic status and a range of genetic markers, the type of school has virtually no effect on academic attainment.