These courses are guaranteed to improve students’ understanding in a significant manner. By getting an overview, they are now more sure of specific parts of the syllabus to focus on; it gives them a good way to strategise their revision.
They will also learn various ways the questions could be asked and can better work on their answering techniques and logical reasoning. It teaches them to focus on key components to score. Provided that students study hard revision after the course, their grades will definitely improve in a tangible manner. The best improvements we have seen go from E to A after 1 course and a few regular lessons.