Ministers came clean on one of education’s worst-kept secrets as they published GCSE league tables this week. They admitted that the annual ritual can lead to schools behaving in ways that benefit the institution rather than pupils.

Schools minister Nick Gibb said that the government wanted to “stamp out” incentives for schools to “game” the system and had reformed the tables to “iron out these idiosyncrasies”.

He identified two problems with league tables that are based on the indicator of five A*-Cs at GCSE (or equivalent) including English and maths. First, the inclusion of “equivalent” qualifications can lead to some pupils “being entered for qualifications more in the interests of a school’s league table position than the child’s own prospects”. Second, the measure has encouraged “weaker” secondaries to focus only on pupils on the C-D borderline, neglecting other children.

But can this kind of behaviour ever be halted while the measure still exists? “I don’t think it can,” warned Brian Lightman, general secretary of the Association of School and College Leaders. “While the key indicators relate to A*-C grades, schools will be bound to focus on getting as many young people as they can through the C-D border.”

The Department for Education is already acting to counter the first problem: from 2014, it intends to remove league table incentives for schools to use vocational qualifications of dubious value. Ministers took more immediate action on the second issue this week by publishing league table data for all secondaries on a new series of measures (see box, page 20), under a plan first announced in May.

But Mr Lightman thinks it unlikely that the achievements of all ability groups and disadvantaged pupils will supplant the importance of the current headline GCSE measure in the eyes of the media. “Newspapers will continue to publish what the public are used to and can understand,” he said. “Vast amounts of additional data are not going to make that more comprehensible.”

The new measures may mean that schools experience additional pressure from prospective parents. But if media rankings are the main reason for schools’ perverse behaviour, then this latest ministerial wheeze stands little chance of stopping it.

It is not just publicity that gives the main GCSE measure its huge significance, but also the importance that the government and Ofsted attach to it when assessing schools. One might think that ministers had already sabotaged their latest attempt to remove its side effects by stating that five A*-Cs including English and maths will “always” be the “most important” “anchor” measure.

Until, that is, you consider the English Baccalaureate. Professor John Howson points out that this measure has had a huge immediate effect, despite it not being made part of schools’ floor targets. “If you are seeing RE and music being thrown out of the window because we are moving to schools doing only EBac subjects, then clearly it has had an influence,” the school staffing expert said. However, he believes that the new multiple measures may not have quite the same impact.

Ministers do have another trick up their sleeves that Mr Gibb did not mention. As Mr Lightman pointed out this week, it is the government’s use of league table indicators for “floor standards”, with the accompanying threat of intervention, that makes it so “dangerous” for schools to ignore them.

The Department for Education has said that, as long as a school’s pupils make at least average progress in English or maths compared to prior attainment, it will not be judged to be below the “floor standard” regardless of its GCSE or Sats results.

If that fails to stop “gaming” of the system, ministers could at least argue that their new measures will allow everyone to see what these rogue schools are up to.

WIDER FOCUS

New GCSE league table measures:

Separate results for low, middle and high achievers (according to Sats results) based on:

- percentage achieving five A*-Cs at GCSE (or equivalent) including English and maths;

- English and maths progress;

- percentage achieving A*-Cs in both English and maths GCSEs;

- percentage entered for and achieving the EBac;

- average grade per qualification, per pupil;

- average grade per GCSE, per pupil.

- value-added measures.

Results of disadvantaged pupils (looked-after pupils and those receiving free school meals) compared with all others based on same indicators, plus:

- average number of qualification entries per pupil;

- average number of GCSE entries per pupil;

- average points score from best eight results (for GCSEs only and for all qualifications).