A Meta-Analysis of Extensive Reading Research

Abstract

The purpose of this study is to investigate the overall effectiveness of extensive reading, and whether learners' ages impact learning from extensive reading differently. The second purpose is to investigate whether the length of time that second language learners engaged in extensive reading influenced outcome measures, and if an effect is found, identify effective periods of time for learners to engage in extensive reading. Meta-analysis was used to investigate the trends shown by past empirical research, chart future research directions, and provide a means to create alternative hypotheses for future research. Two types of empirical studies were conducted: group contrasts of studies that included control groups and pre-post contrasts of studies that only include experimental groups. This meta-analysis included 34 studies that provided 43 unique effect sizes (22 effect sizes for group contrasts and 21 effect sizes for pre-post contrasts) and a total sample size of 3,942 participants. Students who received extensive reading instruction outperformed those who did not. The effect size was small for group contrasts (d = .46) and medium for pre-post contrasts (d = .71). Moderator variables for each contrast were examined to assess the impact of learners' ages and the length of instruction; however, all groups substantially overlapped with each other in terms of their confidence intervals, indicating no statistically significant difference among the groups. There was a small effect size for university students for the group contrast (d = .48), a medium effect for high school students (d = .61), a large effect for university students (d = 1.12), and a large effect for adults (d = 1.48) for pre-post contrasts. In terms of the length of instruction, both one semester of instruction (d = .36) and one year of instruction (d = .52) produced a small effect for group contrasts, while one year of instruction produced a medium effect (d = .74) for pre-post contrasts. In sum, the available extensive reading research to date suggests that extensive reading improves students' reading proficiency and should therefore be a part of foreign language reading curricula.