Data 

https://www.isu.edu/rmc/resources/numeracy-project-resources/

In my opinion, the use of data is the most important part of the process. In coordinating the Georgia Numeracy Project I examined school-wide, grade level, and classroom trends.  I believe it should not be assumed that students' deficit are always due to problems with the students and examining the various trends will allow a clear picture of tier 1 instruction and needs of students.  For example,  if majority of the second grade student cannot count starting from any number within 100, it is clear that we need to make changes to our tier one instruction as these skills should have been mastered in previous grade and it is not a single student but majority of the students. These trends allowed me to make plans for both individualize instruction and school-wide tier 1 instructional needs.