Abstract: To accelerate growth in student achievement, the Los Angeles Unified School District (LAUSD) implemented a Theory of Change with 6 key elements: (a) a coherent academic curriculum; (b) ongoing, site-based professional development; (c) coaching; (d) use of common periodic assessments; (e) collegial, collaborative teams; and (f) active and knowledgeable leadership. This study surveyed staff at 5 LAUSD elementary schools that were in the bottom 10% statewide in 1999, that had made large API gains between 1999 and 2004, and that had principals who worked at the school during that period. Three questions were addressed: (a) the extent that teachers implemented the elements, (b) the degree that principals supported the elements, and (c) which elements contributed the most to the API gains.