CCT conducted evaluation research to inform the development of MyWorld, a learner-appropriate geographic information system, data library, and set of learning activities for middle and high school Earth science, environmental science and geography classes. The My World software and accompanying data and instructional materials are designed to address the needs of learners and teachers for usability and support for developing conceptual understanding of visualization and analysis of geospatial data. Using qualitative and quantitative methodologies, CCT conducted formative and summative evaluations of the MyWorld Project. The design employed (1) pre/post teacher and student surveys in school sites; (2) classroom observations; (3) participant interviews; (4) classroom observation; and (5) pre/post inquiry tests with My World students and non-MyWorld participants.