Most community college students in the U.S. must complete at least one developmental class, such as elementary algebra, before they can enroll in a college-level mathematics course. Increasingly common in such courses is the use of a web-based activity and testing system (WATS). This report presents initial results of a mixed-methods study of elementary algebra learning among 510 students in the classes of 29 instructors across 18 community colleges. Instructors were randomly assigned to use a particular WATS (treatment condition) or their usual approach (control condition). The focal WATS had adaptive problem sets, hints, and videos. Treatment group instructors had access to online support for implementation. For the study, students completed common pre- and post-tests and instructors regularly provided information about their teaching practices. The early results reported here indicate that greater instructor fidelity to developer intentions regarding frequency of assignments are positively associated with greater student learning. [This paper was published in: A. Weinberg, C. Rasmussen, J. Rabin, M. Wawro, and S. Brown (Eds.), "Proceedings of the 21st Annual Conference on Research in Undergraduate Mathematics Education, San Diego, California," 2018.]