Staff can see gains
It's nonsense to imagine you could create an exactly equal assessment every year. The primary teachers I meet are well aware that national tests are little more than window-dressing for government propaganda. The same teachers are, however, convinced by the evidence of their own eyes - as I am - that children's achievement in literacy has definitely improvd over recent years.
There are two reasons. First, the strategy has helped teachers focus on practical support rather than woolly theorising. Second - and more importantly - teachers have shown huge dedication to the task of improving literacy. They've taught a blinder - in spite of tests, targets, paperwork, a malign inspection regime, and the morale-draining rubbish thrown at them by the press (including your recent story).
11 St George's Road, Truro, Cornwall