As part of its work to advance the multiple pathways approach to high school education, the James Irvine Foundation engaged the Bridgespan Group to develop a framework for assessing the nature and needs of the fields in which nonprofits operate. These agents of change often struggle to understand how to focus their field-building investments and activities because they lack a comprehensive and coherent map of the strengths and weaknesses of their field. This framework provides a guide for building more robust fields and can help foundations and nonprofits prioritize their investments. The Strong Field Framework has five components: shared identity, standards of practice, knowledge base, leadership and grassroots support, and funding and supporting policy. Each component is described herein. A toolkit is presented that describes the steps that can be taken to assess the social change field one may be working in. To explain how to use the toolkit, each step is illustrated with a hypothetical application to the field of Early Learning in the state of Washington.