Here is a straightforward explanation about the usefulness of decodable books for children learning to read.
‘The look on children’s faces when they realise how easy reading is – knowing the sounds and connecting them to graphemes on the page. I call decodable text the ‘no tricks books’. They are so simple to use for both teachers, parents and children and importantly decodable text is supported by evidence-based research )from the US, the UK, and the National Inquiry into Teaching of Literacy in Australia.
Thanks to Susan Godsland of www.dyslexics.or.uk for flagging up this article by Maureen Pollard.