Systematic review of retention and learning engagement in online learning from 2015-2025

This study aims to explore retention issues in online learning environments, with a primary focus on the role of learning engagement. Using the PRISMA approach, we analyzed 19 publications addressing engagement and retention in online learning environments from 2015 to 2025. In terms of publication productivity on this topic, 2019 was the most productive year, followed by 2020 and 2022. Regarding learning contexts, more than half of the studies were conducted in MOOC environments. Concerning influential factors of engagement and retention, instructor-related factors or instructional strategies were the most frequently examined, followed by learner-related individual factors and course characteristics. In terms of intervention strategies, games and gamification were the most frequently implemented in these studies, followed by asynchronous online discussions. Regarding types of engagement, multiple dimensions of engagement were most frequently examined, while behavioral engagement was the most studied as a single dimension. This study suggests that engagement is a critical factor in retention in online learning and also reveals an imbalance in the engagement literature with a need for more research on emotional engagement as well as more attention paid to engagement opportunities in various forms of blended learning. Future studies are suggested to explore underrepresented areas that might contribute to enhancing retention in online learning.