This systematic review examines the effectiveness of blended learning approaches in secondary education contexts across diverse global settings. Through a comprehensive analysis of empirical studies published between 2015 and 2024, this research synthesizes findings on the impact of blended learning models on student achievement, engagement, and educational outcomes. Data from 42 peer-reviewed studies representing 15 countries were analyzed using both qualitative and quantitative methods. Results indicate that well-implemented blended learning approaches consistently demonstrate moderate to significant positive effects on academic achievement (mean effect size d = 0.38), with particularly strong results in STEM subjects. Additionally, the review identifies four key implementation factors that moderate success: teacher technological pedagogical content knowledge, institutional support systems, technological infrastructure adequacy, and instructional design quality. The findings reveal that blended learning approaches, when properly implemented with attention to contextual factors, can effectively enhance student outcomes while addressing challenges related to educational access and equity. However, significant disparities exist in implementation quality across socioeconomic contexts. This review contributes to educational practice by providing evidence-based guidelines for blended learning implementation in secondary education settings and identifies critical areas for future research including longitudinal impact assessment and implementation science approaches.
Sustanto et al. (Mon,) studied this question.