Education and Human Sciences, College of (CEHS)



J. Joshua Byrd

First Advisor

Helen Raikes

Date of this Version


Document Type



Byrd, J. J. (2018). Examining Dosage: Comparisons of a High-Quality Program's Impact on Vocabulary and Social-Emotional Characteristics Between One- and Two-Year Cohorts.(Unpublished master's thesis). University of Nebraska-Lincoln.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Child, Youth, & Family Studies, Under the Supervision of Professor Helen Raikes. Lincoln, Nebraska: April 11, 2018.

Copyright (c) 2018 J. Joshua Byrd


This study investigated the effects of high-quality early childhood program dosage by measuring its associations with low-income children’s vocabulary and social-emotional characteristics. The current study also examined the different patterns of annual change between monolingual English-speaking children and Spanish-speaking English Language Learners (ELLs) in two dimensions of language development. The purpose of this study was to explore program impact at two levels of dosage per measure, Group 1 (single year of program) and Group 2 (two or more years of program). Results revealed significant increases in fall-to-spring PPVT-IV scores for English-speaking children in Group 2, significant decreases in Spanish PLS-5 scores for 48-month-olds in Group 2, and significant increases in DECA Total Protective Factors scores for 48-month-olds in Group 2. Limitations of the current study, future directions, and implications for practice are also discussed

Adviser: Helen Raikes