The value of data is increasingly recognized by organizations and programs, including Individuals with Disabilities Education Act (IDEA) Part C and Part B 619 programs. Data can help Part C and Part B 619 program coordinators, data managers and staff improve outcomes for children and families by strengthening their understanding of the needs of the children and families served and by operating the program more efficiently and effectively. Data also are critical for ensuring that all children and families have equitable access, services and supports, and outcomes. Using data to improve programs requires data leadership. Data leaders are defined as those who: (1) build one's own capacity and the capacity of staff and other stakeholders to use data; (2) build and enhance the data infrastructure needed for data collection, management, analysis, reporting and use; and (3) create a culture of data use (e.g., uses data to guide decision-making and sets expectations that others in the organization are expected to do the same). DaSy developed this set of Data Leadership Competencies to support Part C and Part B 619 staff in acquiring the knowledge and skills required to be effective data leaders. Competencies are a set of performance behaviors that are observable, measurable, and critical to successful individual, team, and agency performance.