You may have had the choice of PA or SE estimates. AFIK, PA (prior attainment) is based only on KS1 grades whereas SE involves contextual factors as well. If contextual factors are being taken into consideration, the age of the pupil will have an effect - younger pupils are expected to progress more, all else being equal. Also FSM etc, even post code will have an affect Another consideration is their KS1 maths grades. The maths grade may be one of the factors affecting the KS2 English expected grade. If you are good at maths you must have had a reasonable unserstanding of the words etc the eacher used to teach it. It also works the other way around. It makes sense that someone who is good at English will be able to have a better shot at everything, including maths, than someone who struggles with language.