There is a plethora of general resources on formative assessment available to educators today. What makes our work unique is the specific focus we have on science and mathematics concepts and our approach to making a link between the core ideas in science and mathematics to findings from the research on learning in order to uncover ideas students have that may impede their learning. Our approach to assessment for learning is through a conceptual change process- helping students (and teachers) recognize when an idea they hold no longer works for them. This creates a willingness on the part of the learner (and a challenge on the part of the teacher!) to give up their "misconception" in favor of the accepted scientific or mathematical idea. We think of it as building a bridge between where the learner is to where we want the learner to be scientifically and mathematically, and using data from formative assessment to design instruction that will help students cross that bridge. For some it may be a short bridge, for others it could be a long span. The key is not to correct students and move on but to use their ideas to design learning experiences that promote deep and lasting understanding. To do this teachers need the right tools and understandings of how to best utilize these tools. The books in our Uncovering Student Ideas (USI) series provide teachers with the content specific tools they need to bring about conceptual change. Our professional development helps teachers understand how to effectively use these tools and build a repertoire of strategies that can not only promote learning, but change the culture of the classroom as well.