Xiong, Ellina2021-02-222021-02-222020-12https://hdl.handle.net/11299/218679University of Minnesota Ph.D. dissertation. December 2020. Major: Educational Psychology. Advisors: Jennifer McComas, Kristen McMaster. 1 computer file (PDF); ix, 199 pages.A meta-analysis of group studies and single-case design studies was conducted to examine the effectiveness of vocabulary instruction on vocabulary learning and reading comprehension for English Learners. Overall estimates indicate that vocabulary instruction promoted vocabulary learning and reading comprehension. The mean effect for vocabulary learning was g= 0.40 (CI95= 0.26-0.54, p< .001), a small to moderate effect. The mean effect for reading comprehension was g= 0.26 (CI95= 0.07-0.46, p= .01). Meta-regression was used to conduct moderator analyses, which indicated that differential effects were associated with methodological rigor, instructional programming, and outcome assessments at a statistically significantly level. Findings suggest that comprehensive interventions tend to produce larger effects, but that interventions do not require significant duration, frequency and intensity to produce positive effects. Direction for future research is suggested based on findings from moderator analyses.enEnglish LearnersReading ComprehensionReading InstructionVocabularyThesis or Dissertation