I studied how the grade point averages (GPA, a post-enrollment descriptor) of first-year developmental education students relate to two pre-enrollment descriptors: students' Academic Aptitude Ratings (AAR, a pre-enrollment criterion) and students' voluntary or forced attendance at a mandatory summer-orientation program. Students who involuntarily participated in the orientation had an average AAR score of 94, an average GPA of 2.1, and a 32% chance of being placed on academic probation (i.e, having a GPA less than 2.0) after their first semester of college. However, students who voluntarily attended the orientation had an average AAR of 91, a GPA of 2.9, and an 11% chance of being placed on academic probation after their first semester of college. These results: 1) suggest that developmental education students' voluntary compliance with a pre-enrollment admission requirement (in this case, their voluntary attendance at a summer orientation program) is a strong predictor of subsequent academic success; and 2) AAR scores are poor predictors of the academic success of developmental education students. These results are discussed relative to how developmental education students' motivation toward and involvement in their education contribute to their academic success.