With accurate information, educators are better able to make effective decisions. Besides being used to assess student performance, a complete program of data collection and use can also show educators how management skills, individual learning styles, and other elements affect student achievement. This digest in Spanish provides an overview of how collecting data on student learning in a timely and accurate manner can be used to improve schools. It discusses the role of data in improving education, the types of data that should be collected, the role of teachers as researchers, the effective uses of data, and the steps that schools can take to improve their use of data. (LMI)