Closing the Word Gap with Big Word Club: Evaluating the Impact of a Tech-Based Early Childhood Vocabulary Program

Vocabulary is an important part of literacy skills development, and understanding the effectiveness of various types of programs can help parents, schools, and states decide what to invest in. Programs that use entertainment to engage students to learn (“Edutainment” programs) are popular, but experimental evidence on their effectiveness at teaching vocabulary is sparse. In this paper, we use an RCT to evaluate the effectiveness of a program that uses technology and entertainment to teach vocabulary to children. The program, Big Word Club (BWC), is a web-based platform consisting of animated book videos, dance videos, and music videos intended to help children learn one new word per day. Our field experiment was conducted with 818 Pre-K and Kindergarten students in 47 schools across 3 U.S. states. We randomly assigned schools to a control condition or to use the BWC platform in their curriculum. We find that the program was effective in teaching the vocabulary words that were targeted by the program (0.30 SD) after four months of use. Further, this effect persisted in a follow-up test 2 months later, but only for girls. Treated students also scored higher on a standardized vocabulary assessment (PPVT), but this difference was not statistically significant.