Experimental impacts of a large-scale shared book reading intervention on children's vocabulary development and parental literacy beliefs

Experimental impacts of a large-scale shared book reading intervention on children's vocabulary development and parental literacy beliefs

First Author: Si Chen -- Harvard University
Additional authors/chairs: 
Catherine E. Snow
Abstract / Summary: 

Purpose

Intervention studies find evidence that improving the quality of the home literacy environment can improve children’s language outcomes. However, we know little about Mandarin-speaking children’s home literacy interventions. The iRead intervention is a large-scale home literacy intervention being implemented in a metropolitan area in China. It provides free picture books and parent training sessions for about 50,000 families per year. We ask if the iRead intervention improves (1) children’s vocabulary development and (2) parental literacy beliefs.

Methods

1044 families with children aged 1-3 participated in this study. We used a randomized encouragement design, in which the researcher called randomly selected parents to let them know about the availability of iRead intervention packages and how to access the packages. Six months later, parents from both encouragement and control group took the posttest survey, which (like the pretest) included the Mandarin MacArthur-Bates Communicative Development Inventories and a survey experiment on parental literacy beliefs. We used the random encouragement as an instrumental variable (IV) to estimate the effectiveness of the iRead intervention on children and parents’ outcomes.

Results

We found effect sizes of 22% and 18% on children’s Chinese receptive and expressive vocabulary development. The intervention shows a significant change in parental literacy beliefs.

Conclusion

The iRead intervention is an on-going real-life large-scale intervention that does not set an exclusion on enrollment and cannot randomly select families. We reduced the self-selection bias and provided a robust estimation of the effectiveness of the intervention on children’s vocabulary development and parental literacy beliefs.