“…We have selected 15 studies to emphasize key dimensions of the measurement approach, including sensor-free vs. sensor-based measurement, annotations by the self vs. external observers, unimodal vs. multimodal sensing, lab vs. classroom research, learning activities with varying levels of interactivity, and different validation methods. We prioritized studies that can be considered as pioneering in the field, such as the first study showcasing multimodal engagement measurement in real-world classrooms (Arroyo et al, 2009), the first study emphasizing generalizability beyond the individual (Ocumpaugh, Baker, Gowda, Heffernan, & Heffernan, 2014), or the first person-independent automated measure of mind wandering (Author, year). We acknowledge that our choice of case studies is both subjective and incomplete, but our goal is to provide an overview of a promising new approach rather than review a well-established paradigm.…”