This project will develop and implement a 'proof of concept? model for sharing analyzed video data that draws from two decades of NSF supported longitudinal and cross sectional research on the development of students' reasoning and justifying in K-12 mathematics. Episodes from the collection will be made accessible worldwide to provide an invaluable and unique asset to the field that can be used in creative and effective ways by researchers and providers of in-service and pre-service teacher education through the Internet. Analyzed digital video clips, transcriptions and images of students' work will be linked with analytical commentaries, produced and referenced according to the National Council of Teachers of Mathematics (NCTM) Process Standards for reasoning and justification. Video episodes and supporting materials will be organized into a database and placed on a server for Internet access. In order to make the database contents easily accessible, an indexing scheme made up of attributes or descriptors will be developed and applied, guided by the expertise of a distinguished Advisory Board. The database will be accessible for use by classroom teachers, researchers and teacher educators. The resulting database will enable teachers to study in detail the learning of individual students in classroom settings and in small group work and through individual interviews. A very important aspect of the video data is that it enables one to study how learning actually unfolds. These video tools will make it possible for teachers, teacher educators, and researchers to closely observe students' learning of mathematics and reflect on students' potential for doing mathematics. The collection of video data provides a database for careful analysis and reflection on practice.
