Thanks for the background; I didn't know the history behind why they were set up.
For context, I asked a the question after DD's LA run struggling primary ('requires improvement') became part of a MAT.
We didn't have any opinion either way about academies at the time (still don't tbh; except that more curious now).
We haven't seen any significant difference in the school after the change. DD has now left; four years and two headteacher later, the school still 'Requires improvement' according to ofsted.
Obviously one anecdote doesn't make data, so was looking for whether there are studies on this; whether adopting this structure actually makes a difference in outcome.
From what I found and read here, there doesn't seem to be any, except that mass academic conversion coincided with a period when U.K. school outcomes (as measured by PISA etc) improved. But other things were changing too at the same time (Gove changes etc), so it's probably impossible to extract out the differences academies made on average, if any.
It's probably not worth finding out anymore because after all most schools are academies, and the remaining will eventually become so. In my area all the secondaries are part of some MAT, so there isn't a choice anyway.
The schools that were good in this area before (good by ofsted rating, gcse result), continue to perform well as academies. The schools that were struggling as LA run ones few year back, continue to struggle as academies now.
It probably makes sense - if spending per head is same, if cohort is similar, if no dramatic advancement in teaching techniques have been made since, it's hard to see why outcome would be different under different management structure unless previous management was terribly incompetent. That maybe true for specific cases, but on average across England probably wasn't true.