Data exists in the context of a community that drives data collection and use. The effective use of data can help principals make informed decisions about their policies, practices, and procedures to improve student achievement. The more systematic and thorough principals are about bringing data to the table when making decisions, the more confident they can be that their decisions will lead them to their intended results. Although engaging in the data-driven decision-making process might seem time-consuming at first, in the long run it can greatly reduce the amount of time and resources that might otherwise be spent by moving to action without an intentional examination of what the data reveal about both needs and improvement strategies. This article discusses four steps for using data to make effective decisions: collecting and organizing data, analyzing data, interpreting data, and taking action. This four-step process can be used at any decision level: district, school, grade or subject, and classroom. (Contains 1 figure.)