This brief statement is powerful for me! Engagement can be described in different ways, but if students are busy being "engaged" by selecting user names, avatars or playing a "reward" game of flappy bird, engagement isn't "time on task." Students must be engaged in the content, as the previous statement, for this engagement to qualify as worthwhile. There is a balance, to be sure, of entertainment and education, but it must favor the content of the lesson.