Professor Peter Mortimore, director of the Institute, and Professor Harvey Goldstein, a statistician, have condemned the Office for Standards in Education's report, The Teaching of Reading in 45 Inner London Primary Schools, on the grounds that not one of its conclusions can be supported by the evidence that OFSTED presents.
The most damning criticism by the two professors, in a reply published on Monday, is the suggestion that OFSTED edited its report to "press strongly-held views about aspects of the teaching of reading (and of teacher training)".
"While cherry-picking particular findings and ignoring the quality of the methodology which has led to them may appeal to some policy-makers, it is not a sensible manner in which to manage an education system," the professors write.
OFSTED's report, published in May, has been hugely influential, providing the justification for government policy on the reform of initial teacher training. It also fuelled the backlash against "trendy" child-centred teaching and provoked calls for a return to whole-class methods and the use of phonics in teaching children to read.
The Institute's counterblast argues first that the sample OFSTED used, from Southwark, Tower Hamlets and Islington, three of the poorest boroughs in the country, "is quite atypical of urban education as a whole". Over half the children studied did not have English as their first language, over half were receiving free school meals, and fewer than half were white.
The professors argue that it is impossible to draw inferences about the effectiveness or otherwise of any method unless you measure and compare the same pupils' progress over time - but the OFSTED report's conclusions were based on observing lessons on one occasion. The schools were not revisited.
"It cannot be emphasised too strongly that the analyses carried out are incapable of supporting any reasonable conclusions about school effectiveness. " OFSTED did not gather data on the sort of pupils the 45 schools admitted in Year 1, so it was not possible to assess their progress or the "value added", the professors say.
OFSTED's report also omitted data on turnover of pupils. The professors argue that if, as is likely in inner London, turnover was very high, the pupils' lack of reading capability would have been the fault of another education authority -or even another country.
OFSTED missed the opportunity to conduct an honest investigation into the challenges of literacy in poor urban areas, says the Institute. Instead. it offers "generalised remarks about the use of phonics and whole-class methods". Using the data collected to blame teachers, generalise about the teaching of reading nationally and stress whole-class teaching and phonics "is quite unjustified", the professors conclude.
An OFSTED spokeswoman said the chief inspector stood by the reading report as "a valuable contribution to raising standards of literacy", but she would not be drawn into detailed discussion of the criticisms.
"I don't know why the Institute is doing this," the spokeswoman said."Perhaps for some reason they don't like OFSTED. Chris Woodhead has taken a very strong stance in criticising various things like teacher training."
OFSTED's report also precipitated Chris Woodhead's controversial decision to reinspect 21 of the 68 primary teacher training courses to focus more sharply on how trainees are taught to teach reading. A month ago it emerged that the Institute was one of the 21 earmarked for a revisit, despite it being awarded top grades by the initial inspectors.
The three boroughs involved in the reading survey were delighted by the Institute's critique. Michael Keating, chairman of education in Tower Hamlets, said: "We knew at the time we had been stitched up ... and now the country's leading educational Institute has rubbished the conclusions."
Peter Mortimore told The TES that he had decided to publish this critique because "OFSTED's report has been used to justify so many different things. It is treated as bona fide research but it isn't. The sample is a joke."