This document discusses using student data to inform instruction. It includes examples of different types of student data teachers can collect, such as running records, testing data, student work samples, and conferring notes. The document emphasizes analyzing data to understand what students know and still need to learn, and using data to differentiate instruction to meet individual student needs. Teachers should look for patterns in student performance and tailor their lessons accordingly. The overall message is that systematically collecting and analyzing various sources of student data is essential for properly guiding instruction.