Online learning is extremely prevalent in education, more than ever given the COVID-19 pandemic that has shifted most educational services to an online platform. More specifically, in 2015, close to six million students were taking at least one online learning course, which was 29.7% of all postsecondary students (U.S. Department of Education, National Center for Education Statistics 2018). In 2017, the Online Learning Consortium reported an almost 4% increase in online learning students in 2015 as compared to the previous two years. Although online learning is becoming more prevalent, there has been little to no research to determine what makes online learning most effective. Those that have, either have not compared modalities (i.e., only testing one format) (Sella et al. 2014; Walker and Rehfeldt 2012) or have focused on another aspect of the learning (e.g., does grading anonymously affect performance) (Liu et al. 2018). Determining the components of online learning that lead to better student outcomes will add to the current literature and improve online learning as a whole. The primary purpose of this experiment was to determine what forms of discussion (synchronous vs asynchronous) are most effective in an asynchronous online master-level applied behavior analysis course.