The second paper addressed accessibility issues in the context of ELP assessments for ELs and ELs with disabilities (Guzman-Orth, Laitusis, Thurlow, & Christensen, 2016). The fourth paper dealt with one of the major uses of ELP assessments—the initial identification and classification of ELs (Lopez, Pooler, & Linquanti, 2016). The present paper focuses on summative ELP assessments that states use for accountability purposes. Based on the conversation that took place at the K–12 ELP Assessment Working Meeting on summative ELP assessments, we identify critical policy and research issues. We also highlight the challenges associated with measuring ELP in a diverse group of EL students and recommend ways to embrace and support EL students through shared goals and active communication across federal agencies, state agencies, local agencies, researchers, and practitioners. RELATED REPORTS: • Creating a Next-Generation System of K–12 English Learner Language Proficiency Assessments by M. C. Hauck, M. K. Wolf, & R. Mislevy ETS Research Report No. RR-16-06 http://dx.doi.org/10.1002/ets2.12092 • Conceptualizing Accessibility for English Language Proficiency Assessments by D. Guzman-Orth, C. Laitusis, M. Thurlow, & L. Christensen ETS Research Report No. RR-16-07 http://dx.doi.org/10.1002/ets2.12093 • Key Issues and Opportunities in the Initial Identification and Classification of English Learners by A. A. Lopez, E. Pooler, & R. Linquanti ETS Research Report No. RR-16-09 http://dx.doi.org/10.1002/ets2.12090 • Approaches to Automated Scoring of Speaking for K–12 English Language Proficiency Assessments by K. Evanini, M. C. Hauck, & K. Hakuta ETS Research Report No. RR-17-18 http://dx.doi.org/10.1002/ets2.12147