State and local assessment data from 117 students in one school in the California Central Valley were examined to determine how much participation in a kindergarten through second grade multitiered reading intervention model contributed to third grade reading achievement, over and above the demographic factors of ethnicity, socioeconomic status, parent education level, English language level in kindergarten, gender, and age at kindergarten entry. State and local assessment data were also examined to determine how much participation in a kindergarten through second grade multitiered reading intervention model contributed to third grade reading achievement, over and above the kindergarten reading readiness factors of letter sounds, oral blending, oral segmenting, consonant-vowel-consonant (CVC) word reading, and high frequency word (HFW) reading. Multiple regression analyses with ordered sets of predictors were conducted to identify the relationship of the factors to students' third grade end-of-year reading performance. Additionally, multiple regression analyses were conducted to examine the contributions of three interventions-Systematic Instruction in Phonemic Awareness, Phonics, and Sight Words (SIPPS); "Reads Naturally;" and teacher-created interventions-over and above demographic factors on end-of-intervention assessments. Kindergarten reading readiness and demographic factors significantly contributed to third grade reading achievement, while the effects of participation in a multitiered intervention model were not significant. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]