Automatic engagement estimation in smart education/learning settings: a systematic review of engagement definitions, datasets, and methods.

Background: Recognizing learners' engagement during learning processes is important for providing personalized pedagogical support and preventing dropouts. As learning processes shift from traditional offline classrooms to distance learning, methods for automatically identifying engagement levels should be developed. Objective: This article aims to present a literature review of recent developments in automatic engagement estimation, including engagement definitions, datasets, and machine learning-based methods for automation estimation. The information, figures, and tables presented in this review aim at providing new researchers with insight on automatic engagement estimation to enhance smart learning with automatic engagement recognition methods. Methods: A literature search was carried out using Scopus, Mendeley references, the IEEE Xplore digital library, and ScienceDirect following the four phases of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA): identification, screening, eligibility, and inclusion. The selected studies included research articles published between 2010 and 2022 that focused on three research questions (RQs) related to the engagement definitions, datasets, and methods used in the literature. The article selection excluded books, magazines, news articles, and posters. Results: Forty-seven articles were selected to address the RQs and discuss engagement definitions, datasets, and methods. First, we introduce a clear taxonomy that defines engagement according to different types and the components used to measure it. Guided by this taxonomy, we reviewed the engagement types defined in the selected articles, with emotional engagement (n = 40; 65.57%) measured by affective cues appearing most often (n = 38; 57.58%). Then, we reviewed engagement and engagement-related datasets in the literature, with most studies assessing engagement with external observations (n = 20; 43.48%) and self-reported measures (n = 9; 19.57%). Finally, we summarized machine learning (ML)-based methods, including deep learning, used in the literature. Conclusions: This review examines engagement definitions, datasets and ML-based methods from forty-seven selected articles. A taxonomy and three tables are presented to address three RQs and provide researchers in this field with guidance on enhancing smart learning with automatic engagement recognition. However, several key challenges remain, including cognitive and personalized engagement and ML issues that may affect real-world implementations.