A report from the Centre of Economic Performance at the London School of Economics evaluated the effect of the National Literacy Project, the precursor to the strategy.
Professor Stephen Machin, director of the centre, and Dr Sandra McNally, research officer, compared literacy scores in primary schools with NLP with those and in schools where the programme had not been introduced.
They found the percentage of pupils gaining the expected level 4 in their Year 6 English test increased by 12.2 points between 1996 and 1998 compared to an increase of 8.8 points in non-NLP schools.
They also compared the GCSE results of pupils who had been part of the NLP and those who had not, and found a similar pattern.
Researchers say: "The results of our analysis strongly corroborate the view that the literacy hour under the NLP significantly raised pupil performance in the primary schools that were exposed to it.
"Furthermore, for the first cohort of children exposed to the literacy hour, there is a positive and statistically significant effect of the policy on GCSE results in English at age 16."
By looking at how reading scores affect future earnings, it was estimated how much more pupils could earn as a result of having better literacy skills.
It concludes: "Whichever way one looks at it, the benefits of the literacy hour seem to be large and the costs small."
The Literacy Hour is a forthcoming discussion paper from the Centre of Economic Performance. http:cep.lse.ac.uk
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