This paper describes the genesis of the TRU framework. It explores the dialectic between theorizing teachers’ decision-making and producing a workable, theoretically grounded scheme for classroom observations. One would think that a comprehensive theory of decision-making would provide the bases for a classroom observation scheme. It turns out, however, that, although the theoretical and practical enterprise are in many ways overlapping, the theoretical underpinnings for the observation scheme are sufficiently different (narrower in some ways and broader in others) and the constraints of almost real-time implementation so strong that the resulting analytic scheme is in many ways radically different from the theoretical framing that gave rise to it. This essay characterizes and reflects on the evolution of the observational scheme. It provides details of some of the failed attempts along the way, in order to document the complexities of constructing such schemes.

This article, and my career as an educational researcher, are grounded in two fundamental assumptions: (1) that research and practice can and should live in productive synergy, with each enhancing the other; and (2) that research focused on teaching and learning in a particular discipline can, if carefully framed, yield insights that have implications across a broad spectrum of disciplines. This article begins by describing in brief two bodies of work that exemplify these two fundamental assumptions. I then elaborate on a third example, the development of a new set of tools for understanding and supporting powerful mathematics classroom instruction (and by extension, powerful instruction across a wide range of disciplines) – the TRU framework. In doing so, this paper situates the corpus of work on TRU in a much larger R&D framework.

**Schoenfeld, A.H. (2015). Thoughts on scale. ZDM, the international journal of mathematics education, 47, 161-169. DOI: 10.1007/s11858-014-0662-3. **

This essay reflects on the challenges of thinking about scale – of making sense of phenomena such as continuous professional development (CPD) at the system level, while holding on to detail at the finer grain size(s) of implementation. The stimuli for my reflections are three diverse studies of attempts at scale – an attempt to use ideas related to professional development in two different countries, the story of how research did or did not frame a nationwide attempt at undergirding CPD, and a fine-grained study of the quality of a dozen mentors’ implementation of CPD. The challenge is to “see the forest for the trees,” to be able to situate such diverse studies within a larger framework. The bulk of this article is devoted to offering such a framework, the Teaching for Robust Understanding (TRU) framework, which characterizes five fundamentally important dimensions of powerful learning environments. At the most fine-grained level, TRU applies to classrooms, establishing goals for instruction. But, more generally, it applies to all learning environments, and thus characterizes important aspects of CPD. The paper addresses issues related to the kinds of systemic coherence necessary to make progress on professional development at scale.

*Teaching for Robust Understanding of Essential Mathematics* is based on a presentation at an international symposium entitled “Essential Mathematics for the Next Generation: What and How Students Should Learn” held in Tokyo in 2016. The paper addresses these issues: (1) What mathematics should we teach? and, (2) What are the most important dimensions of rich instructional environments? It describes the Teaching for Robust Understanding (TRU) Framework, and ways in which TRU-related tools can be used in teacher preparation and professional development.

This article undertakes a reframing of the concept of teacher knowledge. It argues that in order to help teachers create more powerful learning environments, a much more general framing is required—one that incorporates a teacher’s perceptions, inclinations and orientations as well as their understandings and related pro ciencies. A main point of departure is the Teach- ing for Robust Understanding (TRU) framework, which focuses on essential dimensions of classroom practice. Questions of teacher knowledge are reframed as: “How can we reconceptualize teacher knowledge (perhaps better, teacher proficiency) so that it encompasses the broad range of perceptions, orientations, understandings and proficiencies that support teachers in crafting learning environments from which students emerge as knowledgeable, exible, and resourceful thinkers and problem solvers? How can it be organized so that it can be worked on productively? This paper explores these issues. It employs the TRU framework as the initial mechanism for reframing, while drawing on Schoenfeld’s (How we think. Routledge, New York, 2010) work on teachers’ decision making and Schoenfeld and Kilpatrick’s (International handbook of mathematics teacher education, volume 2: tools and processes in mathematics teacher education. Sense Publishers, Rotterdam, pp 321–354, 2008) work on teacher proficiency to suggest what should be included in an expanded framing of teacher knowledge.

This chapter describes the synthesis of two powerful approaches to professional development, based on the Teaching for Robust Understanding (TRU) framework and Lesson Study. The synthesis is known as TRU-Lesson Study. In TRU-based professional development, groups of teachers negotiate their visions of teaching and learning collaboratively by reflecting on artifacts of practice using the TRU framework. In math-focused Lesson Study (LS), teachers work together to design, teach, and reflect on a lesson that focuses on key mathematical issues and students’ engagement with them. TRU-Lesson Study, like Lesson Study, profits from teachers’ concerted attention to lesson design and reflection on the hypotheses reflected in the design. Like TRU professional development, it supports teachers to work together explicitly on key dimensions of classroom practice. This paper describes TRU-Lesson Study and provides descriptions of how it plays out in practice.