Single-case design (SCD) methodology, in which data are displayed in a line graph, can be helpful in determining intervention effectiveness in research and practice. Using visual inspection of graphed data, researchers and practitioners can explore the existence of a functional relationship between implementation of the intervention and a particular outcome (Kratochwill et al., 2010). As school psychologists charged with effective data-based decision making, SCD allows us to analyze the effectiveness of interventions for single students or small groups of students, using the individual participant as his or her own control (Horner et al., 2005). This can be particularly helpful when operating in a multitiered systems of support (MTSS) framework (Riley-Tillman & Burns, 2009). Although many aspects of SCD methodology are outside the scope of this article, the authors aim to provide the reader with tips and tools to make the graphical display of data clearer, leading to more accurate analysis and interpretation of student data.