Being a governor involved in performance management assessment, I attended a relevant conference just over a year ago. The lecture was an appalling exposition but I did manage to halt the lecturer when I noticed that external assessors were to see only a sample of teachers’ applications. I asked the sample size to be told that it was 50 per cent. The lecturer was unable to justify this figure.

To my horror, recently an external assessor told me that the sample not only was not more than just 10 per cent but it covered only borderline cases and, further, that the assessor had to go on the judgment of headteachers as to which cases were borderline.

You have said that assessors should only vet appeal cases (13 July). What about error in a headteacher’s assessment that judges a poor teacher to be good?

I consider this to be a far stronger indictment against the use of pound;12m for external assessment than the arguments - though quite valid ones - that you list.

Dr J C Gibbings
Heswell,
Wirralnbsp;