Ask to see raise online so that you can understand what is being demanded of you. It won't just be progress from KS2 - KS4 although it is probably worked out from literacy levels. Raise online is going into great detail with languages as well as humanities due to the e-bacc measurement. You will see which groups are doing better/worse and it will allow you to understand where you need to focus your energies as well as. Broadly speaking all pupils are expected to make 3 levels progress from KS2 so all level 4 children are expected to get a C and level 5 are expected to get a B. If they get an A then that is greater than expected progress in general.