In the past decade, there has been important progress in the development and validation of video-based instruments that enable the systematic assessment of teaching competence with large samples of teachers, across multiple settings and populations, and by researchers other than the developers. This commentary focuses on the methodological contributions represented by the set of articles in this special issue. Several articles report on the development and psychometric properties of innovative ways to measure aspects of the relationship between teaching competence and performance including components of competence, contextual resources for decisions and actions, and knowledge-in-use or accessible knowledge. Others report empirical investigations of the relationships among components of the competence continuum. Still others consider conceptual and methodological challenges in studying instructional competence and performance. This commentary highlights the ways in which the research reported in the articles moves the field forward, providing the community of educational scholars and practitioners with a more nuanced look at the complex constructs of competence and performance.