I teach Synthetic Phonics to secondary students with Reading ages below 7.5. It does work. It is rather more than old /tradiotionsl/organis phonics, highly structured and taught virtually using a script! It has to be taught for an hour each day first thing in the morning, the elements are timed so each element is given the right amount of input and the books are highly structured to complement the elements taught that day. I still taech th 'back of the cornflakes packet and anything else they want to read ' with those whose reading ages come into the next band up.