Reading comprehension is a complex skill: it requires the successful development and orchestration of a variety of lower- and higher-level processes and skills (Balota, Flores d’Arcais, & Rayner, 1990). As a consequence, there are a number of sources for potential comprehension failure and these sources can vary depending on the skill level and age of the reader (Keenan, Betjemann, & Olson, 2008; RAND, 2002). Theories and models of reading comprehension are necessary to make sense of this complexity.