Improving the ability of disadvantaged students to read and comprehend text is also fundamental to the federal education policy aimed at closing the achievement gap between low- and high-achieving students. Title I of the No Child Left Behind Act of 2001 calls on educators to close the gap using approaches shown to be effective through scientifically based research. But such rigorous research is relatively scarce, making it difficult for educators to determine how best to use Title I funds to improve student outcomes. Identifying curricula that improve reading comprehension is part of this challenge. The Institute of Education Sciences has undertaken a rigorous evaluation of curricula designed to improve reading comprehension to meet that research challenge. Four supplemental curricula were selected in a competitive process to participate in a rigorous test of their effectiveness beginning in the 2006/07 school year: (1) Project CRISS by CRISS; (2) ReadAbout by Scholastic; (3) Read for Real by Chapman University and Zaner-Bloser; and (4) Reading for Knowledge by the Success for All Foundation. Results from this study show no effects for three of the curricula and a negative effect for the fourth. (Contains 1 figure.) [For the full report, "Effectiveness of Selected Supplemental Reading Comprehension Interventions: Impacts on a First Cohort of Fifth-Grade Students. NCEE 2009-4032," see ED505578.]