Charter school authorizers (authorizers) that are committed to fostering high-quality charter school options for all students have an imperative to understand the nature of school distress and failure. Authorizers and other stakeholders need to be able to identify and understand schools experiencing distress, long before a state accountability grade designates a school as "failing." In theory, the charter school sector relies somewhat on market forces and family choice to remove unsuccessful schools from the educational ecosystem. However, research shows only roughly 5% of academically underperforming schools are closed annually, on average. When schools are allowed to decline to a point that closure becomes the only option, the disruption of school closure and student mobility often exacerbate the negative effects on students. Rather than wait until a school fails, authorizers may have the ability to identify schools in distress at a much earlier stage. Authorizers often have access to data that allows them to recognize a school in distress at a stage when successful, manageable interventions are possible and the trajectory of hundreds or thousands of students can be improved. While policy contexts and appetites for various interventions and supports will vary for different authorizers, all authorizers can benefit from understanding the leading indicators that often precede a school's decline before decline has affected lagging performance indicators. These early warning signs of a school in trouble provide a good starting point for flagging schools that may need guidance, supports, or simply a more thorough review. Based on the needs of the field, the National Charter School Resource Center (NCSRC) sought to identify and describe characteristics observed in schools experiencing difficulty in achieving the ESEA's definition of a high-quality charter school. This is call these early warning signs indicators of distress. This report provides the indicators of distress authorizers regularly encounter as a school's quality begins to decline. [For "Identifying Indicators of Distress in Charter Schools, Part 2: The Roles and Perspectives of Charter School Leaders and Board Members," see ED616211. For the related toolkit, "Identifying Indicators of Distress in Charter Schools: Tools to Support Authorizer Data Collection," see ED616212.]