A major thrust in assessment reform is the instructional use of assessment (Ministry, 2010). Assessment for learning (AFL) has, however, proven challenging for teachers to implement (Brookhart, 2004; Swaffield, 2011; Tierney, 2006). Researchers have called for studies of classrooms that show how AFL works in practice (Bennett, 2011; Shepard, 2000). This study gathers images of practice from classrooms where teachers have been implementing a structure-based approach called Question Structure. Although a key premise of AFL is that assessment can be used instructionally to support learning, Question Structure’s constructivist-information-processing approach is rooted in educational measurement traditions usually juxtaposed to AFL theory and practice (Broadfoot & Black, 2004). Images of practice were drawn from classroom observation, teaching artifacts, and interviews from teachers who had been implementing the system for three to six years in three Ontario school boards. Data were analyzed through sub-questions emerging from the literature and through grounded theory. The study found that Question Structure supported AFL principles and practices. It also supported a Tylerian, backwards-design approach to program design, but not to excess. Technical revisions tended to evolve into significant change in practice, including program reconceptualization and increased focus on students’ learning. The structure-based approach functioned in a variety of ways, for example to support task clarification, (re)reading and comprehension of text, writing process, open-ended collaborative work, and student-generated questions. Teachers were able to clarify the meaning of ‘structure,’ to distinguish structures from instructional and cognitive strategies, and to use universal structures and strategies as subject-specific pedagogy in Language Arts/English. The role of the technical interest and implications for professional learning are also discussed.