In terms of the sponsored academies judged inadequate, AET has a bigger proportion in this category than any other chain.
Below average (e.g. cf. 65% LA maintained schools good or outstanding):
AET: 12 inspected = 1 outstanding, 3 good, 4 'need improvement', 4 inadequate.
E-ACT: 12 inspected = 2 outstanding, 2 good, 6 'need improvement', 2 inadequate
Oasis: 11 inspected = 0 outstanding, 5 good, 5 'need improvement', 1 inadequate
Above average:
Ark: 8 inspected = 3 outstanding, 4 good, 1 'needs improvement', but none inadequate.
Harris: 9 inspected = 8 outstanding, 1 good
Ormiston: 15 inspected = 7 outstanding, 5 good, 3 'need improvement'
United Learning: 18 inspected = 3 outstanding, 11 good, 3 'need improvement', 1 inadequate
On the other hand I don't know how much weight parents should place on Ofsted reports. There was a really strange story in Private Eye about the CEO of Harris working as a schools inspector in order to visit a competing school in London. Conflict of interest?