States across the nation are creating laws that demand schools use the science of reading. The Rochester School District has been implementing SOR in its structure, assessment, and instruction for more than a decade. In this workshop, we will share our model for implementing Universal Screening in 8 elementary schools. We will collaborate to practice the analysis of authentic data and demonstrate how we use data to plan core instruction and reading intervention. Participants will use the tools provided to evaluate commercial screeners. The presenters will demonstrate how assessment has shaped our successes, or our need for changes, since 2006.