Three out of four academy chains have schools that are 'coasting', according to new research.
The Sutton Trust, a think tank which aims to improve social mobility through education, compiled the Chain Effects 2015 report, comparing the performance of disadvantaged students in academies and other state-funded schools between 2012 and 2014.
The research, carried out by Professor Merryn Hutchings, Professor Becky Francis and Dr Philip Kirby, suggests that disadvantaged students in 11 of the 34 academy chains which were studied were outperforming the average for all state-funded schools.
The research found that in the best performing chains, the proportion of disadvantaged students achieving five good GCSEs (A* to C) was around 15 percentage points higher than the average for disadvantaged students.
The research also discovered that disadvantaged students in 17 of the 34 chains improved faster than the national average from 2012 to 2014 when all performance measures were considered.
Education Secretary Nicky Morgan recently defined 'coasting' schools as those that consistently fail to ensure 60% of their pupils achieve five good GCSEs, including English and Maths.
And she said that to improve their results, coasting schools would face being converted into academies in the future.
But 44% of the individual academies analysed in the Sutton Trust study were below the Government's new 'coasting' level in 2014 and 26 of the 34 chains had at least one coasting school.
Academies are schools run by charities or businesses and paid for directly by central government rather than local councils.
Sutton Trust chairman Sir Peter Lampl said: "Many chain sponsors, despite several years in charge of their schools, continue to struggle to improve the outcomes of their most disadvantaged students."
The trust is urging the Government to include a measure of attainment for disadvantaged pupils in its new criteria for coasting schools.
The study identified a number of attainment measures including the percentage of disadvantaged students achieving A* to C at GCSE or equivalent (including English and Maths), the percentage making expected progress in English and Maths and performance in the English Baccalaureate (EBacc).
Among the highest performers were academies sponsored by education charity Ark, known as Ark schools, which has 32 primary and secondary schools in London, Birmingham and the south of England.
Sir Peter said: "The best academies benefit from good leadership and good teaching, which provides an outstanding example to others that continue to face challenges."
Nansi Ellis, deputy general secretary of the Association of Teachers and Lecturers (ATL), said: "This report confirms the Government's own recent evidence that in nine of the 20 larger chains, pupils made significantly below average progress. It also shows that only 10 of the 100 larger local authorities performed as badly.
"The most important result is that two of the three 'successful' chains and 12 of the 'successful' LA's are London-based, where much of their success is down to the collaboration of schools in the London Challenge.
"Academisation is not the answer to schools' problems, and there is no robust evidence, overall, that academies nationally outperform other types of school. The Education and Adoption Bill is undemocratic in forcing academisation without consultation and excludes the school from selecting the sponsor that is most appropriate to them."
A Department for Education spokesman said: "It is wrong and misleading to try to classify coasting schools based on 2014 data alone. A coasting school can only be identified based on performance over three years, so we won't know until 2016 which schools they will be.
"The academies programme has transformed the lives of millions of pupils, particularly those from disadvantaged backgrounds, as this report shows. We are already working with many excellent academy sponsors and are recruiting more to pair with struggling schools so every child has access to the excellent education they deserve."
Tristram Hunt MP, Labour's shadow education secretary, said: "David Cameron's first Education Bill of this parliament does not contain a single concrete measure for tackling under-performance in academy schools, despite the fact that more than half of all secondary schools are academies.
"The Tories think that the way to turn around under-performing schools is to simply turn them into academies and then walk away. They have no plan for those academies that are struggling, leaving them to fail or 'coast' and letting down the children who attend them.
"Labour understands that it takes more than this to drive up standards in our school system. We need a strong focus on raising the quality of classroom teaching and support for head teachers, greater collaboration between schools at a local level, and robust local oversight of schools to stop under-performance going unnoticed and unchallenged."