As far as the primary sector is concerned, no self-respecting statistician would dream of pretending to draw valid conclusions when such tiny cohorts are involved. In the secondary sphere, two factors that radically affect what can be achieved continue to be ignored.

First, in spite of Government recognition of the importance of sound reading skills, no allowance is made for the on-going effect of this factor, which is largely outside the secondary schools’ control.

Second, an important part of the teacher’s job is to maximise the contribution that children make to learning. In particular, teachers have to overcome the non-quantifiable effects of broken, insecure, uninterested or even hostile homes. This “pupil factor” varies without pattern and will always thwart attempts to assess accountability.

Value-added data have enormous potential for school self-evaluation, but the value-added tables book is misnamed and is not worth the expensive candle.

JOAN CONSTANCE

Retired teacher 26 Thorold Grove, Sale, Cheshire