In this presentation, we discuss the interplay between theory and one particular method of data collection: eye-tracking. Eye-tracking promises various opportunities for research, in particular for studying students’ attention, strategies, and even collaboration in so-called dual eye-tracking (DUET), and has gained increased interest as a research method. Still, researchers acknowledge that eye-tracking data interpretation is difficult and ambiguous and often needs to be complemented with other sources. In this talk, we discuss two studies in which we aimed for a triangulation of eye-tracking with other research methods. In both studies, ontological and epistemological questions are intertwined.