McREL Study Examines Effects of Raz-Plus on Reading Achievement and Motivation

Research Applies to: Raz-Kids, Raz-Plus

About this Research

In this independent study, McREL International examined the effects of Raz-Plus on the reading skills and motivation to read of K–5 students. The study was a randomized controlled trial meeting rigorous standards of research in order to identify a causal relation between Raz-Plus and reading skills and motivation.

ESSA Evidence Level: Strong

This study meets strong evidence standards because it used a well-controlled experimental design and produced statistically significant positive effects with a large sample size across multiple sites.*

Main Findings

Students whose teachers used Raz-Plus showed significantly higher levels of reading achievement and significantly higher levels of interest in both academic and recreational reading, compared with students whose teachers did not use Raz-Plus. The effect sizes were 0.14 for reading achievement, 0.63 for interest in academic reading, and 0.57 for interest in recreational reading.


Participants were 662 students in grades K–5 in rural schools in the Southeastern United States serving predominantly low-income and minority populations.

Study Design and Procedures

This study used a randomized controlled trial design in which classrooms were randomly assigned to either the treatment group (Raz-Plus) or the control group (standard curriculum used by the schools). Students in the treatment group used Raz-Plus three to five times per week for 60–90 minutes each time, on average, for 13 weeks. Students in both groups completed pre- and posttests for reading achievement, as measured by the STAR assessment, and for interest in reading, as measured by the Elementary Reading Attitude Survey (ERAS).


Ho, H. (2018, August 30). Efficacy study of Raz-Plus, a blended learning platform for K–5 reading. Denver, CO: McREL International.

*Source: U.S. Department of Education (2016). Non-regulatory guidance: Using evidence to strengthen education investments. Washington, DC: Author.

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