The use of data to track and manage progress is critical to a collective impact initiative achieving results or understanding impact. Yet, little research has been done to determine how collective impact practitioners can effectively use data. This article--including a literature review, semistructured interviews with experts on performance management and collective impact, as well as Living Cities' experience with over 70 collective impact initiatives--outlines five steps for practitioners to grow their initiative's capacity to use data: Agree on the Data; Find the Data; Present the Data; Discuss and Learn from the Data; Change Behavior and Share Responsibility.