Attending a grammar school may not automatically improve a child’s chances of scoring good GCSE grades, according to a study.
It suggests that the type of school a child goes to has little impact on their academic achievement.
The research also indicates that pupils who go to selective (grammar and private) schools are genetically more likely to do well in exams.
The study, by researchers at King’s College London (KCL) is based on an analysis of over 4,000 students in England and Wales.
It took into account factors such as family background, achievement at age 11 and cognitive ability as well as measuring “polygenic scores” – which involved looking at genes linked to educational achievement.
There are thousands of genetic variants that are linked to educational achievement that have a tiny effect individually, but when added together can have an impact on a student’s chances of doing well in exams, the study notes.
The findings, published in the journal npj Science of Learning, show that on average, students in non-selective schools had lower polygenic scores for academic achievement compared to those in selective schools.
Overall, three times as many students in the top 10% of polygenic scores went to a selective school, compared to the bottom 10%.
Looking at GCSE results, the researchers found that students at private and grammar schools scored around a grade higher across English, maths and science, than their peers in non-selective schools.
But once factors that are involved in selection are taken into account – like ability, previous academic achievement and socio-economic status – there was less than a 10th of a grade difference in results.
In terms of polygenic scores, these only played a small part in the differences between exam grades, and researchers said it is too early to tell how much genetic factors have an impact on the difference between exam results in selective and non-selective schools.
Lead author Emily Smith-Woolley said: “Our study suggests that for educational achievement there appears to be little added benefit from attending selective schools.”
She also said: “Although school type appears to have little impact on achievement at GCSE, there are many reasons why parents opt to send their children to selective schools.
“Further research is needed to identify if school type makes a difference in other outcomes, such as university and career success.”
Controversial proposals to lift the ban on creating new grammar schools were a key plank of the Conservative manifesto in last year’s snap general election, but the plans were dropped in the wake of the election result, which saw the Tories lose their overall majority.
But grammars can still take on more pupils under rules that allow good state schools to expand.