Why, when so many educational interventions demonstrate positive impact in tightly controlled efficacy trials, are null results common in follow-up effectiveness trials? Using case studies from literacy, this article suggests that replication failure can surface hidden moderators--contextual differences between an efficacy and an effectiveness…

This experimental study aimed to replicate and extend a previous efficacy study of an elementary grade content literacy intervention that demonstrated positive effects on students' vocabulary knowledge depth, argumentative writing, and reading comprehension. Using a cluster (school) randomized trial design, this replication experiment was…

There are several goals guiding this study. First, the authors use an experimental design to examine the causal effects of giving children 10 self-selected books over two summers. Second, they examine whether treatment effects are moderated by children's family income (i.e., eligibility for free- and reduced-price lunch). As a result, they examine…

The authors describe an independent evaluation of the READ 180 Enterprise intervention designed by Scholastic, Inc. Despite widespread use of the program with upper elementary through high school students, there is limited empirical evidence to support its effectiveness. In this randomized controlled trial involving 312 students enrolled in an…

This paper has three goals. First, it describes the broader research on summer reading loss. Second, it discusses how research and development efforts informed the key components of Project READS (Reading Enhances Achievement During Summer), a scaffolded voluntary summer reading intervention for children in grades 3 to 5. The second part of the…

In this article, the author examines the troubled history of the relationship between research and practice in the area of early reading instruction. He describes how researchers have historically addressed controversies about reading instruction and explains why good research seems to have a delayed and limited impact on reading policy and…

Social science research suggests that reducing class size has its largest effects on the achievement of minority and inner-city children during the first year of formal schooling. Despite scholarly disagreements about the implications of specific studies on class size, economists generally agree that targeted class-size policies rest on stronger…