REL Southeast conducted a randomized control trial in the Mississippi Delta to test the impact of a kindergarten vocabulary instruction program on students’ expressive vocabulary. The study titled, The Effectiveness of a Program to Accelerate Vocabulary Development in Kindergarten (VOCAB), found a significant positive impact for student’s vocabulary development and academic knowledge, as well as for the classroom instruction outcome of vocabulary and comprehension support. In addition:
Kindergarteners who received the K-PAVE intervention were one month further ahead in vocabulary development at the end of kindergarten compared with their peers who did not receive the intervention. However, there were no statistically significant differences between the two groups on measures of kindergarten listening comprehension.
The kindergarten teachers trained in the program were significantly more likely than their peers who did not receive K-PAVE training to engage in activities intended to support students' vocabulary and comprehension development. However, the program did not produce a statistically significant impact on either instructional or emotional support in the classroom. Additionally, the program did not impact the amount of instructional time spent on literacy in areas other than vocabulary and comprehension.