Une possibilité?

??
J'ai du mal à comprendre "scrap learning"..... par rapport à sa "définition".
Ce serait plutôt que l'élève ne retient que des "scraps" (les 20%, on suppose).
J'ai utilisé ce site pour m'inspirer.
http://cursus.edu/article/5549/comment-les-apprenants-retien...

"Unfortunately, using training as a performance lever tends to lose its power with time as employees forget what they’ve learned or let their newly acquired skills go unused. XXX said that after training, learners typically fall into one of three categories:

1. They do not try to apply training.
2. They attempt to apply it but realize no worthwhile results.
3. They apply training and get some positive results.

Positive results tend to be reinforcing and prompt the learners to apply their skills again. Yet X estimates that successful application, group three, is as low as 20 percent. The remaining 80 percent is known as scrap learning — learning that was delivered but unsuccessfully applied, as in groups one and two, and is therefore wasted."

I don't think there is a set phrase in French.

proposé