Date of Award


Publication Type

Doctoral Thesis

Degree Name





assessment, dual-route, french immersion, lexical decision tasks, neuropsychology, reading


Casey, J.E.




Defining deficits in reading ability may be accomplished through the analysis of a child’s reading tendencies, representing a possible paradigm shift in the conceptualization and assessment of reading disabilities. Based on this premise, Mohl and colleagues (2018) developed a quantitative paradigm to measure reading tendency in children through performance on two lexical decision tasks (LDTs) that differentially rely on decoding and sightword reading abilities. The Reading Tendency Index (RTI; Mohl et al., 2018) is calculated from the differential between drift rates on the phonologic and orthographic LDTs. Scores closer to zero represent a balanced approach whereas scores as a negative or positive value suggest the tendency to rely on phonological decoding or sightword reading strategies, respectively. It was suggested that a balanced approach promotes more proficient reading abilities; however, this original study was performed with a small, male-only sample with a significant number of children with an ADHD diagnosis. The present study provided independent examination of the RTI paradigm, including the two LDT tasks and original calculations, to validate the tasks as a measure of reading abilities in a larger, representative sample of school-aged children. The present study involved the following goals: 1) to replicate the three-group reading tendency structure based on LDT performance in a larger representative sample of school-aged children, 2) to examine the construct validity of the RTI groupings and LDT tasks as a quantitative measure of reading ability, 3) to determine whether RTI group membership can be predicted based on reading and other cognitive skills, and 4) to explore performance differences, if any, in participants enrolled in French Immersion programs. The final sample included 92 participants aged 7 to 14 years (Mage = 9.96 years) recruited from English (n = 49) and French Immersion (n = 43) schools. Results indicated the following: 1) the three-group RTI structure was replicated in the larger sample of typically-developing school-aged children; 2) Sightword Readers had poorer performance on reading fluency, reading comprehension, and spelling than Balanced Readers and Decoders, but groups did not differ otherwise; 3) only reading comprehension predicted membership for the Sightword group; and 4) French Immersion students demonstrated similar patterns of performance on the RTI and other cognitive measures as English-only students. Supplemental post-hoc analyses were performed to explore different cut-off scores and methods for determining RTI groups. Implications and limitations of the current findings as well as considerations for future studies are discussed.