The four papers presented in this symposium describe the first year and a half of a two-year study designed to examine and increase the linkage between assessment and instruction in classroom decision-making. The first year of the project was devoted to a review of the literature, development of a taxonomy interrelating measurement concepts essential to instructional decision-making, identifying contexts in which interpretation of measures of learning could be helpful, and examining tangential information related to home environments. The result was the development of The Data Box, and integrated set of materials designed to help teachers investigate the use of assessment data in instructional decision-making and ultimately to increase their own use of assessment data. Pilot data on a field review of The Data Box and data gathered at workshops indicated positive attitudes of teachers toward the Data Box and positive ratings of the workshops. A post-implementation evaluation will be carried out in May 1981. The level of teacher morale and the self-perceived needs of teachers had a great influence on the reception of The Data Box by teachers. (BW)