I understand the explanation that students are very good at predicting their performance in terms of their learning but I don’t understand the mechanism or link that has caused such a large effect size?

I understand the explanation that students are very good at predicting their performance in terms of their learning but I don’t understand the mechanism or link that has caused such a large effect size? Does it mean that as a teacher I actually limit their learning when I don’t let students set appropriate and challenging learning goals? Do I as teacher need to nurture and encourage students to have high expectations?

Answer: Yes, aiming to raise student expectations about what they can achieve is the key and providing success (worked examples, etc.) can increase the expectations that students have, along with associate increased self-efficacy or confidence to reach these higher expectations. It is indeed not more complicated than that, but it is too rare as students learn that they need to hand something in, work till the bell, and many other performance (and not mastery) notions of learning.