Faculty members and their corresponding academic fields at the University of Puerto Rico at Bayamón are classified with regard to grading practices over time. Based on the effects on the intercept of the equations that predict the GPA and the proportion of student withdrawals observed in each of the 39,337 courses offered during 41 consecutive terms, faculty members and academic fields are scaled from the easiest to the most difficult. Evidence points to the conclusion that the courses of the most difficult academic fields are offered primarily by the hardest grading faculty members and attended by the most academically able students, while the courses of the easiest academic fields are offered primarily by the easiest grading faculty members and attended by less academically able students. The conclusion of such self-sorting processes is reinforced by evidence from maximum likelihood models demonstrating that the probability that a randomly selected faculty member behaves like a high-grader or a low-grader is highly and significantly related to the cluster of academic fields to which the faculty member belongs. Such a probability is also strongly and significantly influenced by the heterogeneity of student academic ability distribution. Hence, faculty members are very responsive to signals sent by their students' characteristics. This empirical result deserves further detailed analysis given that it implies a scenario in which faculty members and students engage in a shopping-around process in which both parties free-ride from each other, altering institutional norms and academic standards.