Oasis and the disappearing GCSE pupils

Oasis Community Learning featured in an article by investigative journalist and education expert Warwick Mansell in the Guardian last week. Mansell was following up allegations and concerns that some supposedly 'high performing' schools had seen high numbers of GCSE pupils 'removed' from their rolls and sent to other schools or educational facilities. The concern expressed in the article was that these schools, many of them part of high-profile academy chains like Harris and Oasis, might be massaging the number of pupils who actually sit their GCSEs and filtering out pupils on academic grounds in order to artificially raise their results. Mansell's investigation found that Oasis had three schools among the 50 schools with the largest reduction in the number of pupils sitting their GCSEs over a year.

Are Oasis filtering out pupils who might drag their results down? Is that the sort of practice parents in Waltham Forest want to see in their local schools? Or would we be better off without Oasis altogether?