<![CDATA[This study addressed the need to strengthen science literacy in the Indonesia–Papua New Guinea border region through Culturally Responsive Teaching (CRT) by developing and validating a context-appropriate teacher readiness instrument for indigenous communities. The instrument was specified as a multidimensional model encompassing pedagogical knowledge, efficacy, school contextual support, culturally responsive planning and materials, culturally responsive assessment, and community collaboration. A layered, cross-sectional validation was conducted: expert judgment for content validity, target-user assessment for face validity/readability, a limited pilot (approximately 30 respondents), and confirmatory factor analysis (CFA) on the main sample; measurement invariance (MI) across gender, years of service, and certification was tested sequentially. Content validity met predefined standards: all items achieved I-CVI ≥ .78 and S-CVI/Ave = .917; qualitative feedback prompted the alignment of terminology and local examples without altering construct coverage. Internal reliability was adequate (α and ω ≥ .70). CFA indicated acceptable fit; most loadings were ≥ .50; CR ≥ .70; AVE ≥ .50; and discriminant validity was satisfied. Measurement invariance was established up to the scalar level for gender and certification, and up to the metric level for years of service; comparisons of latent means by years of service therefore require a partial scalar approach based on the problematic indicators. A known-groups test showed a practically meaningful difference between certified and non-certified teachers (Cohen’s d ≈ 0.63; p < .05). Overall, the instrument is culturally adapted and empirically validated, enabling program evaluation and targeted professional development toward inclusive, culturally responsive science education.]]>
