Date of Award


Degree Type


Degree Name

Doctor of Philosophy in Psychology


School Psychology



First Advisor

Susan Loftus-Rattan


Direct and early vocabulary instruction is particularly important for children with low levels of vocabulary knowledge as they are at risk for later reading difficulties (Biemiller & Slonim, 2001). It is recommended that, through direct and systematic instruction, these children be exposed to and learn what Beck, McKeown, and Kucan (2013) regard as Tier 2 vocabulary words, a subset of approximately 7,000 word families. Given that the words in this grouping differ widely across various word properties yet are taught using relatively fixed strategies, research inquiry surrounding word difficulty is warranted. Within the context of a Kindergarten vocabulary intervention study, the current study (N=853) investigated the relationship between two word properties, concreteness and syllable count, and Tier 2 vocabulary word learning outcomes over time, while controlling for differences in the length of time between instruction and assessment of vocabulary words. Results suggest that target word concreteness significantly predicts short-term and long-term learning outcomes when measured expressively, but not receptively; and that target word syllable count significantly predicts short-term learning outcomes when measured expressively, and short- and long-term learning outcomes when measured receptively. Implications for these results are discussed.



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