I have had a policy from the beginning with my students that as long as the grading period is open, they can fix mistakes on assignments and resubmit for full credit. This is an effort to encourage mastery of content. I also grade the journals they are required to maintain in my class. If students only take the notes I give, they can earn a solid B on their journals. If they actually add their own notes, interpret the notes into their own wording, or use the journals to ask questions they can bring that grade up to an A. In doing so, this does give students control over this portion of their overall grade. Giving them this control helps to eliminate that feeling of helplessness when they do poorly on an assignment and become haunted by that grade. Thus, students who are persistent in their attempts to maintain their grades as well as those that persist in understanding content do much better in my class.