Reading comprehension is an essential skill for success in school and post-school life. However, despite the importance of this skill, a considerable number of students in the U.S. have shown difficulties in reading comprehension. According to the 2015 National Assessment of Educational Progress (NAEP) of the National Center for Education Statistics (NCES, 2015), 31% of 4th graders and 24% of 8th graders did not meet the basic level of reading comprehension. This study focuses primarily on the reading performance of fourth-grade students in that the grade is a crucial point where students begin learning how to read to learn. The purpose of this present study is twofold--(1) to identify patterns of cognitive attributes of reading comprehension (e.g., retrieving, inferencing, integrating, and evaluating) of fourth grade readers at different proficiency levels and (2) to explore how these attributes affect reading comprehension by using PIRLS (Progress in International Reading Literacy Study) 2011 data of the U.S. According to the framework of PIRLS (Mullis, Martin, Kennedy, Trong, & Sainsbury, 2009), each question assesses one of the attributes associated with different item formats (e.g., multiple choice and constructed responses) and text type (e.g., narrative and expository text), specifically how these item formats and text types affect reading comprehension achievement will be examined. To accomplish the purpose, this study will apply two different approaches, the person-oriented approach and the variable-oriented approach. Specifically, this study will explore the individual students' patterns of strengths and weaknesses of the attributes at different proficiency levels by employing Cognitive Diagnostic Models (CDMs) (person-oriented approach) and then examine the influence of those attributes to reading achievement by applying factor analyses (variable-oriented approach). Based upon the results, the structure of reading comprehension attributes and implications for interventions of struggling readers will be discussed. Finally, limitations and future research directions will be provided. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]