XP assignments: pupils taking easy option!
When I set my classes XP assignments for completion at home, I've noticed that many of them do just exactly what you'd expect them to do: they go to Basics 1 and rack up the points as quickly as they can, no matter how much further through the course they really are. (Children are so clever, aren't they?) Is there a way to prevent this?
The short answer is no. If your classroom has a specific course set (rather than "no specific language", you can set a specific skill for them to complete.
The most effective assignments aren't available through the Duolingo for Schools interface, though. I would prefer to set my students to achieve a particular place on the tree, and then keep it gold.