Christine Gilbert, the head of Ofsted, suggests that inspectors found schools in poor areas to have been transformed by traditional discipline (“Ofsted reveals winning formula”, February 27). As evidence, she cited 12 schools that have registered markedly improved GCSE results.

The problem with the “analysis” is that no account has been taken of changes in intake, which has been found in study after study to be the main determinant of school outcomes.

Ofsted extols the trajectory of Greenwood Dale School in Nottingham, for example, but it neglects to mention that Greenwood Dale has had a continuously falling number, and share, of pupils from families in poverty, from 49 per cent of all pupils in 1997 to 30 per cent in 2006, and still falling. Once these changes are taken into account, Greenwood Dale performs no better, and no worse, than it ever did and than other schools nearby.

The easiest way for schools to appear to improve their raw scores is to alter their intake, both on entry and via subesquent suspension and expulsion. This simply passes some harder-to-teach pupils to another school.

It is good that Greenwood Dale is now nearer the local average intake. But let us not be misled into thinking that this represents any real improvement in education, or that the 12 schools cited can tell us anything more than their neighbours could about the way forward for the system. Like academies, specialist schools and a host of other recent initiatives, this is sham school improvement.

Professor Stephen Gorard, School of education, Birmingham University.