Difference between ISEB/CEM test?

[mumof420]

What is the difference between ISEB and CEM tests for 11+? is there certain schools that use one or the other?

They are both online tests with different formats. I think ISEB is easier but not certain. They are sometimes used as a stage 1 exam with another exam for those with the best marks. St Paul's, Westminster and Reeds use it. CEM is used by some grammars, St John's and I think I saw comments on it being used for Radnor House. Both formats can be practised on Atom Learning.