Her research interests include theory-driven inquiry-based science curricula, developing valid and reliable assessment instruments to measure inquiry learning, using authentic scientific practices in K-12 classrooms, using technological tools to enhance students' inquiry-based learning, and scaling locally successful curricular projects to culturally and ethnically diverse settings. Hee-Sun is also interested in designing and developing research methodologies that can allow researchers to conduct ecologically valid studies in real classroom settings. Hee-Sun directs the assessment activities for the TELS and CLEAR projects.