Schools minister Nick Gibb has said he wants to stamp out practices which see schools prioritise their ranking in exam league tables ahead of ensuring all pupils get a good education. New league tables for England, out next week, show which schools boost pupils\' progress between the ages of 11 and 16. Mr Gibb said the previous system allowed schools to exploit the tables. He told the Daily Telegraph some weaker schools focused on a small number of pupils in order to boost their ranking. \'Incentivise schools\' Writing in the paper, he explained: \"The purpose of performance tables must be to incentivise schools to raise standards and to enable parents to make informed decisions when choosing a school.\" But he added: \"The way school league tables have evolved over the past two decades can encourage a degree of \'gaming\' by some weaker schools, desperate to keep above the standard that would trigger intervention by Ofsted or the Department for Education.\" Schools minister Nick Gibb Mr Gibb says some schools have been able to abuse the system Mr Gibb said that, since 1997, the number of C grades awarded had increased because weaker schools had been incentivised to focus on them. He said this meant students who could have gained As were getting Bs, and E-grade students who were capable of achieving Ds had been neglected. \"We intend to make available data formerly kept secret in the Department for Education,\" Mr Gibb wrote. \"For example, we want to show how well secondary schools educate those children who left primary school still struggling in the 3Rs. \"The new tables will have a column showing the proportion of such children who went on to achieve five or more GCSEs at grades A* to C. We can then compare schools to see which are better at helping children who started from this low base.\" The figures will also highlight how well a secondary school educates those students who joined them as high achievers and will show how well schools improve the chances of pupils who have come from poorer backgrounds, Mr Gibb said. Last year the league tables were overhauled to show results in the English Baccalaureate - or EBacc - which records achievement in five core subjects.