Dosage effects on language, literacy, and general development for children enrolled in multiple early intervention programs

Abstract

This study examined dosage effects of multiple intervention programs on young children’s language, literacy, and general development. By employing a hierarchical linear model on a sample of 1,436 children from 72 classrooms, developmental outcomes of four-year-old children simultaneously receiving differing numbers of intervention services were compared: Group 1: Pre-Kindergarten only, Group 2: Pre-Kindergarten + Early Reading First, Group 3: Pre-Kindergarten + Early Reading First + Head Start. Additionally, the effects of previous participation in Early Head Start/Head Start before age four as well as the effects of classroom quality on child outcomes were examined. Findings suggested that understanding the primary focus areas of each program was a key to understanding the dosage effects of multiple intervention programs on children’s developmental skills. Also, integrating additional intervention programs within a limited time frame may not necessarily lead to greater gains in child outcomes because positive and negative effects of a specific program might negate the effects of other programs. Having additional days of participation in Early Head Start and/or Head Start before age four positively predicted the developmental gains children made at age four in the areas of physical and cognitive development. A pattern of relationships between classroom quality and child outcomes revealed a close alignment between quality features and the particular child outcomes considered. Policy implications regarding the appropriate level of intervention dosage were discussed.