Using data for decision-making is critical for schoolwide leadership teams and has been shown to enhance both social and academic outcomes for students (Faria et al., 2017). Using data effectively, however, requires that teams have a clear vision about the type of data, format of data presentation, and process for using data. To avoid expending resources on data collection that is not well used, we recommend building decision-systems rather than data systems. Start with the decisions a team will make, provide the team with the relevant data, and establish a protocol for using data in making team decisions. Teams need to have the right data in the right format at the right time in order to make efficient and effective decisions. In this Practice Brief we propose that there are at least four core types of data needed by high school [Positive Behavioral Interventions and Supports] PBIS Leadership Teams and that these data can be used to problem-solve at the (a) whole school, (b) at-risk group, or (c) individual student levels. We encourage each school team to review the data currently available in their school for effective decision-making and consider possible revisions to their information systems, as appropriate or if needed.