“…Consistent with this assessment, Mu et al (2022, p. 4) talk in their literature review about "evidence for construct-underrepresentation" in various conceptualizations and measurements for teaching quality in mathematics education. Such topic-and concept-specific features could include the understanding of a particular mathematical topic such as the Pythagorean theorem (Drollinger-Vetter, 2011), or topic-specific basic conceptions (e.g., Salle & Clüver, 2021;vom Hofe, 2003) or key concepts (e.g., Gravemeijer et al, 2017) and are also known as "robust criteria of understanding" (Schoenfeld et al, 2014). Topic-specific elements of understanding are based on normative views about a particular mathematical topic and describe the object of understanding in its breadth and depth.…”