Successful preparation for and passage of algebra remains a major gateway to pursuit of science, mathematics and technology related careers. Students in urban settings in rational number reasoning (RNR), including multiplication and division, fractions, ratio reasoning, scaling, similarity, and the related ideas of decimal and percents. This configuration of topics is also known as the Multiplicative Conceptual Field (Vergnaud, 1983). This project will synthesize the research literature in this area to strengthen urban practitioners' knowledge of how to prepare students for this critical filter (Sells, 1973). It will implement an innovative approach to construct a new resource base composed of three interrelated elements: a) a bibliographic database of studies with coded and searchable characteristics and abstracts, organized into a visual web of authors, works, and topics, b) a data cube of RNR topics, types of reasoning skills, and grade bands that maps the rich array of assessment items used in these studies to national standards, and c) a synthesis of the work into a conceptual corridor in both visual and narrative formats. The project will interlink these databases to permit teachers to follow an effective conceptual sequence as much as can be identified, while generating relevant assessment items for their students, and identifying related readings for their own professional development.