A mixed-methods framework for assessing differentiated instruction implementation barriers in EFL secondary education contexts

This article presents a methodological framework for systematically investigating barriers to differentiated instruction implementation among English as Foreign Language (EFL) teachers. Our method combines:-15-item Likert-scale questionnaire measuring teacher perceptions across three domains: teacher preparation, classroom implementation challenges, and institutional barriers-A structured classroom observation protocol assessing nine key indicators of differentiated instruction implementation-Statistical validation procedures establishing instrument reliability (Cronbach's Alpha 0.869) and observation consistency (Cohen's Kappa 0.81)This dual-instrument approach was applied to six EFL teachers in an Indonesian secondary school context, revealing significant discrepancies between theoretical knowledge and classroom practice. The framework effectively identified that while teachers possessed reasonable knowledge of differentiation principles (<i>M</i> = 2.50, SD=0.98), process differentiation strategies were implemented by only 33 % of participants. This methodology enables researchers to triangulate self-reported perceptions with observed practices, providing a comprehensive understanding of implementation barriers in language education contexts.