“…Previous techniques adopted to measure flow experiences, such as electroencephalography (EEG), eye trackers, interviews, and questionnaires, presented limitations as high cost and the impossibility of conduct a massive application [17,20,21]. A more recent and promising approach is to measure flow experiences through the use of data logs of students in learning systems [17,18,19,22]. However, this field is still poorly explored, and there is a lack of empirical data-driven study to investigate the relation between the users' data logs and their flow experience in gamified educational systems [17,18,19,20,23].…”