When children play the reading games in the Ultra eBooks (indicated by the orange star button on certain pages), we assess their reading skills. Once a child has played enough (i.e. answered enough questions), we are able to make an assessment of their reading level. If they are not being challenged, we move them up to a more challenging level. If they're struggling, we move them down to an easier level. If they're being adequately challenged, we keep them at their current level. Level up events take place at the start of a new read and not during a reading session.