The design studio pedagogy fosters a learning by designing model for students to develop designing skills. A methodology, based on protocol analysis and the FBS framework, is proposed to measure actors’ design cognitive behavior and interaction throughout design critiques. Those metric measurements provide a quantitative understanding of their design activity during the critiques. A case study of four architectural critiques of a team of two students, across a semester, illustrates our methodology. The results point out differences in each actor’s behavior, and their evolution across sessions.