Just How Important is Discipline?

Our current education system, Common Core, focuses on improving the students' critical thinking. However, it overlooks an important aspect of education-- discipline. Over the times, our education system has been declining in strictness, and thus leading to less obedient students. I believe that this is a major flaw in our education system. As can be seen in Barboza's Article, "Shanghai Schools' Approach Pushes Students to Top of Tests," simply having obedient students can have a profound effect on their test scores--though at the cost of their ability to think critically. What do you think? Is discipline truly an important factor in the education system?