31 August 2017 Schools weeding out poorly performing students? It's the same ruthless logic as sports League tables reign supreme. Getty Images Sign UpGet the New Statesman's Morning Call email. Sign-up This practise of weeding out less academically gifted students has been an open secret amongst this country's best independent and grammar schools for years. This week The Guardian reported that students were taking legal action against a high-performing grammar school as they believed they had been unfairly asked to leave. The students had not achieved the minimum B average asked by the school, St. Olave’s Grammar, to continue into their final year of sixth form. The practice is thought to be widespread, but St. Olave's appears to be an extreme case, as they reportedly asked 16 students to leave after Year 12 for not achieving the B average. The school is believed to have asked more students to leave the previous academic year. But why do such schools care so much about removing these students, who may not be as high achieving as their other students? Browse through any Mumsnet discussion on the topic, and the reasoning clear - it's all about league tables. The head of a prestigious independent school who asked not to be named told the New Statesman that schools in the top 50, “perhaps inevitably, became obsessed by holding on to their positions”. And that once these schools realised league tables could tell “a good story”, the tables had been “corrupted” and “thereafter began the culling of the kids – notably at 16 – who would not help the school’s A level showing.” But surely such a small number of students cannot make that much of a difference? You'd be surprised. The Department of Education's new system of scoring A-Level results is based on two primary measures: the percentage of students who in their final year get AAB or above, and the average point value of a student's grades. This point value system is brand new. It works by scoring an A* as 60 points, an A at 50 points, a B at 40 points and so on till an E which is 10 points. The top school in the country last year, St Paul's Girls' School has a point average per student of 54.44. So the average grade of their average student is higher than an A. Eton? The most famous school in the country has a point average of 50.72 - it is a languishing 16th in the country. The difference between the top five schools is a mere 2.5 point average. This is not the Premier League, where last year the champions Chelsea had 93 points and 16th place Burnley had only 40. The league tables for A-Levels are very fine margins. Each student who fails to achieve these high gradesschools can signficantly affect a school's league position. The influence of a handful of low achieving students is magnified by the generally fewer number of students admitted into the top sixth forms in the country: The smaller the sample size, the larger the effect of an outlier on the average. The competition of the league table system can also be reasoned similarly as to why athletes dope. Lance Armstrong's justification for doping in cycling was that everyone was doing it and that if you didn’t, you would be left behind. Schools which are less rigorous with weeding out their less academically gifted students fall further behind in the league tables. Professor Simon Burgess, who has conducted research on school performance tables noted that making this data public can hold badly performing schools to account, and as shown by research conducted after Wales abolished league tables in 2001, leads to higher attainment in students, especially among those from disadvantaged neighbourhoods. Burgess does acknowledge that the current loop-hole of removing students mid-way through their studies “should stop” and that it’s “definitely wrong”. But he also argued that no parent is actually moving their families half way across the country to attend a school that might perform slightly better in these league tables. He also states that “some schools may disproportionally care about being first, or first in their town as opposed to doing a great job for all their pupils”. Kevin Courtney, General Secretary of the National Union of Teachers added that “the more schools define success in terms of competitive exam results, the harsher the educational environment will become.” Ultimately with these top schools, like top athletes - it's a numbers game. › 20 years after Diana's death, we still do not want the royal family to be happy Jason Murugesu is a postgraduate student in science communication at Imperial College London, and a former Wellcome Scholar at the New Statesman. Subscribe For more great writing from our award-winning journalists subscribe for just £1 per month!