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Effectiveness
Findings
The WWC review of English language learners addresses student outcomes in three domains: reading achievement, math achievement, and English language development.
Reading achievement. Carlo et al. (2004) did not present the actual means for English language learners in the article. They appeared in a graph but could not be easily accessed with precision. The lead author provided the WWC with these students' pretest and posttest means and standard deviations on each outcome measure. The WWC analysis of the English language learner subsample found no statistically significant differences on reading achievement (performance on cloze passages), but the effect was large enough to be considered substantively important by WWC standards.
English language development. Carlo et al. (2004) did not present the actual means for English language learners in the article. They appeared in a graph but could not be easily accessed with precision. The lead author provided the WWC with these students' pretest and posttest means and standard deviations on each outcome measure. The WWC analysis of the English language learner subsample found no statistically significant and no substantively important impacts on the Peabody Picture Vocabulary Test-Revised (PPVT-R), and the Morphology measure. The Word Mastery impact was statistically significant; the multiple word meanings and word association impacts were substantive positive. The average effect across the five measures of the domain indicated potentially positive effects on English language development
Rating of effectiveness
The WWC rates the effects of an intervention in a given outcome domain as: positive, potentially positive, mixed, no discernible effects, potentially negative, or negative. The rating of effectiveness takes into account four factors: the quality of the research design, the statistical significance of the findings (as calculated by the WWC8 ), the size of the difference between participants in the intervention condition and the comparison condition, and the consistency in findings across studies (see the WWC Intervention Rating Scheme).