Using the A* grade to select university applicants is a purely administrative fix. (“The A* offer is already here: Cambridge demands 90%”, March 20). Admissions tutors are deluded if they think an A* student will be more able than one with an A. The exam’s error of measurement means that, for many, the award of an A or an A* will be down to luck. The only rational solution is to set realistic minimum entry requirements and then select by lottery - but we all know what Ed Balls thinks of lotteries.

George Bethell, Director, Anglia Assessment, Bardwell, Suffolk.