This document is the first in a series of working papers that elaborate on a framework of four key stages in moving toward a common definition of English learner (EL), as described in the Council of Chief State School Officers (CCSSO) publication, "Toward a "Common Definition of English Learner": A Brief Defining Policy and Technical Issues and Opportunities for State Assessment Consortia" (Linquanti & Cook, 2013). It summarizes a national working session of state and consortium representatives, experts and stakeholders held on September 18, 2013 at the Washington, DC offices of CCSSO. Specifically, the working session deliberated on the CCSSO guidance document's first stage--identifying a student as a potential English learner--in order to build understanding and consensus among assessment consortia, participating states, and other stakeholders on key issues, and on strengthening related policies, practices, and tools. The authors planned and facilitated the working session under the auspices of the CCSSO English Language Learner Assessment Advisory Committee, which is funded by the Carnegie Corporation of New York, with in-kind support from the WIDA Consortium and Understanding Language Initiative of Stanford University. An appendix is included of participants and represented institutions who attended the National Working Session on Identifying Potential English learners. [See: Toward a "Common Definition of English Learner": A Brief Defining Policy and Technical Issues and Opportunities for State Assessment Consortia at ED542705.]