This article is the third in a series describing the steps in using data-based decision making to inform intervention and, ultimately, improve outcomes for children. Whereas the first two articles describe identifying and measuring important behaviors to target for intervention, the purpose of this article is to describe basic considerations in the third step in data-based decision making: interpreting graphed data through visual analysis. The goal is to provide the reader with basic knowledge to interpret child performance data to inform decision making. First, a basic graphic framework for organizing performance data is presented. Second, elements of visual analysis, or the ways data are evaluated, are reviewed with discussion of considerations and procedures for interpreting data. Finally, attention is given to how to use graphs to inform instruction and intervention. Case vignettes are used throughout to illustrate the use of graphs and visual analysis. (Contains 2 tables and 5 figures.)