The researchers found that the Israeli scheme had much less effect on teaching methods in middle schools than in elementary schools.

ECONOMIST: Not helpful

Those have been cut both at the state and federal level, which has an effect on the sort of teaching offered.

ECONOMIST: A quirk of history faces a new challenge

According to the report schools which did less well often showed "a lack of clarity about the intended impact of the spending", did not monitor the effect properly and often spent the cash "indiscriminately on teaching assistants".

BBC: Schools could do better with pupil premium, says Ofsted