Texas legislation mandated that colleges offer developmental education using a corequisite model, where students concurrently enroll in introductory college-level courses with supplemental developmental support. Using data from the population of Texas students in developmental education, we estimated regression models to investigate differential relationships between corequisite characteristics and outcomes, both overall and by student characteristics. Our findings suggest there is no single "magic bullet" course structure that is universally more effective, as relationships between the reform and student success vary by subject and student subgroup. Additionally, even a single credit of corequisite developmental support can be beneficial for some students, potentially more so than traditional three-credit courses. [This is the online first version of an article published in "Educational Policy."]