School improvement without will and moral purpose--without a genuine commitment to all students--is an empty exercise in compliance that, in the authors' experience, can do more harm than good. The authors have seen educators use data to "more accurately" track students, further widening the opportunity-to-learn gap. In response to achievement gaps, one school mandated lunchtime tutoring for all black students, regardless of whether or not they failed the state test (Confrey & Makar, 2005). Avoiding these and other data-based disasters is an ethical matter that begins with will, passion, and determination. This article explores six critical assumptions that underlie collaborative data work to improve school for all students. These assumptions serve as a catalyst to clarify an educator's thinking as well as for dialogue with colleagues in using data to improve teaching and learning.