Edwards, Lynn2016-09-192016-09-192016-06https://hdl.handle.net/11299/182260University of Minnesota Ph.D. dissertation. June 2016. Major: Educational Psychology. Advisors: Matthew Burns, Amanda Sullivan. 1 computer file (PDF); xi, 156 pages.The purpose of the current study was to use a conceptual model to identify possible causal mechanisms at play in the phrase drill (PD) intervention. The study was carried out by isolating and investigating modeling and sentence repetition, which are two specific instructional components that are typically used in PD, by creating instructional variations of PD that separated the two components into two levels (low and high conditions). The study used a two-by-two factorial, between-subjects experimental design with a control condition. Participants were 111 second grade students attending elementary school in the upper Midwestern United States. The participants were identified as being below benchmark on a grade level curriculum-based measure in reading. Participants were randomly assigned to one of the four PD intervention conditions or the control condition. Each participant received one session of one of the intervention conditions or the control. Participants were assessed using a reading fluency measure looking at both accuracy and reading rate. Results indicated modeling functions as a potential causal mechanism of the PD intervention but sentence repetition does not function as a causal mechanism. Secondly, the results provide evidence for the effectiveness of the PD intervention in increasing struggling second grade readers’ ability read words accurately in connected text. Third, the results lend preliminary support for using the instructional hierarchy conceptual model to identify causal mechanisms of reading interventions specifically in the area of the acquisition stage of the hierarchy. The results of the study were contextualized within theory and previous research. Implications for practice, directions for future research, and limitations of the study were also addressed.enacademic interventionscausal mechanismsreading fluencyreading interventionsThesis or Dissertation