As the ongoing national indicator of what American students know and can do, the National Assessment of Educational Progress (NAEP) in Reading regularly collects achievement information on representative samples of students in grades 4, 8, and 12. Through "The Nation's Report Card," the NAEP Reading Assessment reports how well students perform in reading various texts and responding to those texts by answering selected-response and constructed-response questions. The information NAEP provides about student achievement helps the public, educators, and policymakers understand strengths and weaknesses in student performance and make informed decisions about education. The 2019 NAEP Reading Assessment will measure national, regional, state, and subgroup achievement in reading but is not designed to report individual student or school performance. The assessment will measure students' reading comprehension and their ability to apply vocabulary knowledge to assist them in comprehending what they read. The reading assessment will use the same framework used in 2009. This document presents the conceptual base for and discusses the content of the assessment. [For the 2017 report, see ED604441.]