Grading practices are known to influence student behavior and learning, particularly in introductory physics courses. To study these influences, we must gain an understanding of how students think about grades with respect to the poles of effort and mastery that shape some popular alternative grading strategies. We administered a survey about grading to N = 88 introductory physics students, with a combination of free-response and numerical questions. The free-response questions generated feedback about students' experiences with stress related to grades and their perspectives on how grades represent effort and mastery. The numerical question asked about their preferences for how grades in a physics course weight their understanding of course material and their effort toward completing coursework. The numerical responses reveal that just over half our introductory students weighted effort more heavily than understanding. Filtering these numerical responses by students' discussion of stress, effort, and mastery reveals insights into their thinking about how grading is structured.