Contentious debate abounds on the way in which reading development occurs , how it should be supported , and the instructional methods and materials that are the most efficacious. Two issues recur continually within this ongoing debate: The role that assessment plays and the form this should take . The proposed research addresses these two areas. The longitudinal research proposed involves the experimental evaluation of two two-tier support models for emergent literacy skill development: Children's Progress Academic Assessment (CPAA) as a stand alone assessment and intervention package (Model A); and CPAA combined with Precision Teaching, a specialised instructional methodology, (Model B). The aim of the research is to compare the efficiency and efficacy of Model A and Model B. The objectives of the research are to assess each models capacity to: lessen the gap between struggling and skilled readers; reduce the number of students identified as requiring special education services; accurately differentiate between those students requiring supplemental instruction, and those with reading disabilities. Participating schools will be randomly assigned to the following groups: Model A (MA) schools, Model B (MB) schools, and control schools (CS). The skills needs of all students will be identified in the three schools using the CPAA assessment. All students will reside in the primary tier of instruction which is the general education provided in the classroom. In both MA and MB schools two-tier models of reading intervention will be implemented. The secondary tiers of instruction will be delivered to students in MA & MB schools, identified as requiring additional instruction by CPAA assessment. In MA schools CPAA differentiated intervention will be implemented. In MB schools interventions will be delivered using Precision Teaching (PT) to target the skills needs identified by CPAA. CS schools will run the assessment component of the CPAA but will not deliver the differentiated tuition identified by the CPAA, or targeted PT instruction. The research hypotheses are as follows: MA will prove more efficient than MB; MB will prove more effective than MA; over time, students' scores in both formative and norm-referenced reading assessments will be higher in MA and MB than in CS schools.