No amount of manipulation of the GCSE results for value-added purposes (TES, December 9) should obscure some basic principles. First, value added, as understood in this context, is a means of making league tables more acceptable, even though the GCSE is meant to measure pupils' achievements rather than put them into a rank order.
Second, the implicit definition of "value" - ie, performance in the GCSE exams - is so narrow that it is seriously misleading. No matter how important high grades (which are not necessarily the same as good exam results) are, we should not allow them to represent the value that a good school contributes to a pupil's all-round education.
Even within the narrow reference of performance in exams, no one has yet devised a reliable means of calculating for a pupil the relative importance of the schoolteacher factor and the pupil abilityhome support factor. Until someone does, all the various computations, indexation figures and so on, will be based on invalid premises.
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