This quantitative, quasi-experimental study investigated the reading achievement of students at-risk of failure to learn to read. This study analyzed the effectiveness of the reading intervention program, Reading Success, which is used with at-risk first grade students in an elementary school district in DuPage County, Illinois. The Reading Success program is an early intervention program developed by educators who expanded upon proven, research-based intervention programs for emergent readers. The program claims it helps students make greater gains in developing reading skills than those who do not receive the intervention and assists students in closing the achievement gap, raising literacy skills to a level equivalent to their non at-risk peers. The study was designed to determine whether students who participated in the Reading Success intervention demonstrated accelerated growth in literacy skills. The study compared the Reading Success group with a group of at-risk students who did not receive the intervention to determine whether the Reading Success group made greater gains in literacy skill development. The study also compared the Reading Success group at the end of the intervention with their non-at-risk peers to determine if students "closed the gap" and were able to reach the non-at-risk category. Finally, the study looked at achievement scores to determine if students maintained the level of achievement one year after completion of the intervention. The study analyzed student achievement on the Illinois Snapshot of Early Literacy, fluency assessments, and the Stanford-9 literacy measures. The findings of this research study indicate that the Reading Success intervention did not have the expected impact on students in first grade. The data analysis revealed that students who received the reading intervention did not close the achievement gap. In fact, the students in the Reading Success group did not even outperform the at-risk students who did not receive the intervention. Based on the findings in this study, the district should explore the administration of the Reading Success intervention, focusing on the integrity and fidelity of program implementation. The district should also explore other reading intervention programs that may be more effective in increasing the literacy skills of at-risk learners. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]