Guided Reading and EFL Comprehension Outcomes: A Cluster-Aware Quasi-Experimental Study among High School Students

Abstract

Reading comprehension remains a persistent obstacle for EFL high school students, yet rigorous, classroom-level evidence on the Guided Reading Method (GRM), with adequate control for baseline ability and class clustering, remains scarce. This quasi-experimental, pretest–posttest, control-group study compared GRM with conventional instruction among 250 students (n = 125 per group) across 20 intact 10th-grade classes in an Azerbaijani public high school over an eight-week intervention. Groups were equivalent at baseline (pretest: M = 14.46 vs. 14.68, t(248) = −0.34, p = .738). Posttest scores rose to M = 19.20 (32.78% increase) in the GRM group versus M = 16.27 (10.83% increase) in the control group. A linear mixed-effects model (Posttest ~ Group + Pretest + (1|Class)) confirmed a significant adjusted GRM advantage (b = 3.12, SE = 0.59, z = 5.32, p < .001, 95% CI [1.97, 4.27]; ~10.4% of the 30-point scale), supporting H1; ICC = .079 indicated 7.9% of variance attributable to classroom clustering. The unadjusted gain-score effect was large (d = 0.92). The Group × Domain interaction was non-significant (χ²(3) = 2.39, p = .496), indicating a generalized rather than domain-specific benefit; H2 was not supported. These findings provide evidence that structured Guided Reading can produce a measurable, broadly distributed comprehension advantage for adolescent EFL learners under classroom conditions.