The inclusion of value-added data in the publication of the resultsnbsp;for primary schools is welcome, if long-overdue, and shows that manynbsp;schools that up to now were assumed to be good schools were just goodnbsp;at attracting high-attaining students.

However, even value-addednbsp;scores don’t adequately reflect the very high levels of success that teachers at inner-city schools have achieved with their students, fornbsp;two reasons.

The first is that we know that the presence ofnbsp;high-achieving students increases the scores of other students at thenbsp;school, presumably by making it easier to create an academic ethos.

Parents may not care whether their children succeed because they arenbsp;well-taught, or because there are lots of high-achieving students atnbsp;the school, but if we want to know how well the teachers are doing,nbsp;then we must control for this effect.

The second is that the amountnbsp;value-added to the students achievement during a key stage depends,nbsp;to put it bluntly, on how much cash their parents have.

There are many schools whose success has been secured as much by the parents’nbsp;willingness to pay for private tuition as by the difference made bynbsp;the school.

The new performance tables may be a better measure of thenbsp;performance of students, but they don’t tell us very much at allnbsp;about the quality of teaching at a school.

It is time that such tables came with a health warning - relying on them to choose a school could seriously damage your child’s education.

Professor Dylan Wiliam
Assistant Principal
King’s College London